Open Access
Add to BibSonomy
Abstract
We demonstrate that the transverse polarization-sensitive photoresponse of the CuSe/Se nanocomposite film deposited on a transparent substrate depends on whether the film is irradiated from the air side or substrate side. In particular, the nanosecond photocurrent pulse is either bipolar or unipolar pulse depending on which interface beam hits first. The observed phenomenon can be described in terms of the interplay between counter-propagating photocurrents generated at the air/nanocomposite and substrate/nanocomposite interfaces due to the surface photogalvanic effect. Our experimental findings can be employed to control the amplitude and temporal profile of the photoresponse by changing the polarization of the excitation laser beam.
© 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
1. Introduction
Polarization-sensitive photocurrents generated on the surface of conductive solids are associated with photon drag and surface photogalvanic effects (PDE and SPGE, respectively). They can be observed in media of any symmetry [1] and show a strong dependence on the polarization and incidence angle of the excitation laser beam [2,3]. The PDE originates from the transfer of the photon momentum to a charge carrier [4,5], while the SPGE is due to the optical orientation of the photoexcited charge carriers [6] followed by their scattering on the sample surface [3,7–9]. At oblique incidence, the PDE and SPGE give rise to the longitudinal and transverse photocurrents, which propagate along and perpendicular to the plane of incidence, respectively. The longitudinal PDE photocurrent can be observed at any polarization of the excitation beam, while the longitudinal SPGE photocurrent vanishes if the excitation beam is s-polarized. The transverse PDE and SPGE photocurrents are forbidden for both s- and p-polarized excitation beams, however, the transverse PDE photocurrent vanishes if the light penetration depth is longer than the electron mean free path in the material [10].
Although PDE has been extensively studied in thin films and 2D materials [11–22], the SPGE has attracted much less attention of the material physics and nonlinear optics communities. In particular, to the best of our knowledge, the SPGE has not been studied in semitransparent semiconductor films, in which it should lead to the photocurrent generation at both front and bottom surfaces of the sample [23,24]. That is, by measuring the SPGE photocurrent in such a material one may perform a comparative study of photoelectrons scattering on air/semiconductor and semiconductor/substrate interfaces. We have recently demonstrated [9,25,26] that the SPGE is responsible for the longitudinal and transverse photocurrents in the semitransparent stoichiometric CuSe films and the films comprising CuSe nanocrystallites in amorphous Se matrix. Therefore, one may expect that in the CuSe-based films, measurements of the photoresponse can be employed to visualize the scattering of the photoexcited electrons at the substrate/film and air/film interfaces. It is worth noting that being a transition metal chalcogenide, CuSe possesses unique electrical and optical properties and can be employed in solar cells, photodetectors, photothermal converters, microwave shields, etc. [27–32].
In this paper, we study the photoresponse dependence of the film composed of CuSe and trigonal-Se (t-Se) nanocrystallites on the polarization and incidence angle of the femtosecond laser pulse. We demonstrate that the transverse photocurrent generated in the film deposited on a glass substrate is dominated by the SPGE, however, the photoresponse of the film essentially depends on the direction of the excitation beam propagation. Specifically, when the femtosecond pulse hits the air/nanocomposite interface first, the photoresponse manifests itself as a unipolar current pulse. In contrast, when the femtosecond laser pulse hits the glass/nanocomposite interface first, the photocurrent pulse is bipolar. This phenomenon can be explained in terms of the interplay between counter-propagating SPGE photocurrents generated at the air/nanocomposite and glass/nanocomposite interfaces.
Our experimental findings can be employed to control the amplitude and temporal profile of the photocurrent pulses by changing the polarization of the excitation laser beam. They will also open avenues towards the development of new approaches for probing the electronic properties of semiconductor interfaces and for the development of the fast and broadband devices capable of visualizing the polarization state of the laser beams in the spectral range spanning from ultraviolet to infrared with the nanosecond temporal resolution.
2. Experiment
In the experiment, we studied the 115 nm thick CuSe/t-Se nanocomposite film obtained by thermal vacuum deposition technique described in Ref. [25], where t-Se is trigonal selenium. Briefly, the Se/Cu bilayer was deposited on the rectangular (15×35 mm) glass substrate at room temperature at a residual pressure of 10−3 Pa. Specifically, the Se and Cu granules were successively vaporized during the single vacuum cycle in such a way that the hot Cu and Se particles moved along the substrate surface normal. The hot Cu clusters deposited onto the fusible Se layer initiated spontaneous explosive crystallization that lead to the formation of the CuSe nanocrystallites. In order to improve crystallinity, the film was annealed in vacuum for 40 min at the temperature of 500 K. The annealing resulted in the transformation of the amorphous selenium remains into t-Se nanocrystallites.
We revealed the phase composition of the deposited film by processing the measured X-ray diffraction pattern [see Fig. 1(a)] using the TOPAS 4.2 structure analysis software [33,34] which enables determination of the lattice parameters of the nanocomposite constituents. Specifically, we showed that the synthesized CuSe/t-Se film is composed of 75% wt. CuSe (hexagonal lattice parameters a = 3.94 Å and c = 17.13 Å at the lattice microdistortion of 0.1%) and 25% wt. t-Se (trigonal lattice parameters a = 4.35 Å and c = 4.94 Å at the lattice microdistortion 0.01%) nanocrystallites having sizes of >100 nm and 20 ± 9 nm, respectively. The average sizes of crystallites and crystal lattice distortions were determined using the double Voight approach. By comparing the obtained diffraction pattern with that of CuSe powder one may conclude that the growth of the CuSe crystallites occurs mainly in the (006) plane [Fig. 1(a)]. SEM image of the film surface, which is shown in the left part of Fig. 1(b). In the SEM image, one can observe star-shaped entities, which are presented at higher spatial resolution in two insets on the right. From the upper right inset to Fig. 1(b) one can see that CuSe nanocrystals are coated by smaller t-Se crystallites, which partially hide CuSe crystal planes (see Fig. 1(b), the bottom right inset).
Fig. 1. (a) Measured X-ray diffraction pattern of the synthesized CuSe/t-Se nanocomposite film and X-ray diffraction resonances of CuSe (PDF 00-034-0171) and t-Se (PDF 00-042-1425) powders. The CuSe/t-Se film is composed of 75% wt. CuSe and 25% wt. t-Se nanocrystals having sizes larger than 100 nm and 20 nm, respectively. (b) The SEM image of the film surface. (c) The optical transmittance spectrum of the 115 nm thick CuSe/t-Se film.
At the wavelength of 795 nm, the transmittance of the 115 nm thick film is 23.6% [see Fig. 1(c)] and the film complex refractive index is n = 1.8 + 1.8i. Since the light penetration depth exceeds the electron mean free path in the CuSe/t-Se nanocomposite, one may conclude that the PDE does not contribute to the transverse photocurrent [10,19], i.e. it originates from the SPGE. It is worth noting that the choice of the film thickness was dictated by both the measurement setup and the film morphology. Specifically, we demonstrated experimentally that if the film thickness exceeds 300 nm, the film tends to crack, while in thinner films, the signal is suppressed by the high inter-electrode resistance. In addition, in order to observe the interplay of the currents generated at both interfaces, the film should be thin enough to ensure that light intensity at the second interface is sufficient to produce SPGE current. The photocurrent was excited by pulses of Ti:S laser having an energy of 100 µJ with a duration of 120 fs at the wavelength of 795 nm and a repetition rate of 1 kHz. In preliminary experiments, we showed that the damage threshold of the film is as high as 110 GW/cm2. Since the light intensity used in the photoresponse measurements did not exceed 12 GW/cm2, no light-induced modification of the sample was observed.
We measured the amplitude and temporal profile of the photovoltage U, which was generated between the gold electrodes deposited on the film surface parallel to the plane of incidence σ. The inter-electrode resistance was 35 Ω. The measured photovoltage is proportional to the transverse photocurrent j = U/r, where r = 50 Ω is the input impedance of the oscilloscope (LeCroy 42 Xs) with a bandwidth of 400 MHz and rise time of 875 ps. The laser beam, which is linearly polarized along the x′ axis in the plane of incidence σ (see Fig. 2), passes through a half-wave plate and hits the film at the incidence angle α. We control the polarization azimuth Φ of the incident beam by rotating the half-wave plate by the angle φ = Φ/2. At φ = 0 and φ = 45 deg, the incident beam is p-polarized (Φ = 0) and s-polarized (Φ = 90 deg), respectively. In the experimental configurations shown in Figs. 2(a) and 2(b), the laser pulse is incident on the air/film and glass/film interfaces, respectively.
Fig. 2. Sketch of the experiment for the CuSe/t-Se film irradiated from the air (a) and substrate (b) sides. The upper part shows the film with attached electrodes A and B, which are parallel to the plane of incidence σ; no and ne are fast and slow axes of the half-wave plate. The polarization azimuth of the incident beam is Φ = 2φ, where φ gives the orientation of the fast axis. The lower parts show the projections of the experimental arrangements on the YZ plane and counter-propagating SPGE photocurrents. Temporal profiles of the photovoltage generated between electrodes A and B are also shown.
Since CuSe has direct and indirect band gaps of 1.43 eV and 1.02 eV, respectively [35], the absorption of the photons having the energy of 1.558 eV (795 nm) results in the interband transitions. The ensemble of the photogenerated electrons in the conduction band has anisotropic momentum distribution due to the optical orientation [2,3,6,8,36] (see Fig. 3). If the beam is not s-polarized, at the oblique incidence it produces the same number of electrons moving towards and away from the interface. However, an electron moving towards the interface will lose its momentum faster than the electron moving away from the interface. This asymmetry manifests itself as the SPGE photocurrent. Since the sign of the SPGE photocurrent is determined by the direction of the surface normal [7], the currents generated at the air/nanocomposite and nanocomposite/glass interfaces propagate in opposite directions (see also Fig. 3). It is worth noting that since the transmittance of the CuSe/t-Se film is as low as 23.6% at the wavelength of 795 nm, the SPGE generated at the air/film interface is higher than that generated at the film/substrate interface.
Fig. 3. Qualitative illustration of the longitudinal photocurrents generation when the excitation beam hits the air/film interface first. The counter propagating SPGE photocurrents generated at the air/film and film/substrate interfaces are also shown.
3. Results and discussion
Our measurements revealed that the transverse photocurrent does not depend on the position of the laser beam spot on the film surface at all α and Φ provided that the electrodes are not irradiated. It is worth noting that irradiation of the nanocomposite/metal interface will result in the generation of the polarization-sensitive photocurrent due to a Schottky barrier [37,38], “hot” electrons [39] and local surface plasma resonance in the anisotropic plasmonic nanostructure [40].
One can observe from Fig. 4, that in our experimental conditions, the amplitude of the photovoltage pulse generated in the film is a linear function of the excitation pulse energy. That is, the polarization-sensitive photoresponse of the film can be described in terms of the light-to-current conversion efficiency η = U/rEin, where U is the measured photovoltage, Ein is the incident pulse energy.
Fig. 4. Dependences of the photovoltage generated at the irradiation of the air/film interface at the angle of incidence of α = 45 deg and polarization plane azimuths of Φ = ±45 deg on the excitation pulse energy.
Figure 5(a) shows that the conversion efficiency is proportional to the sin2Φ, i.e. the transverse photocurrent vanishes for the p-polarized (Φ = 0) and s-polarized (Φ = 90 deg) excitation beams. We also demonstrated that the conversion efficiency is an odd function of the incidence angle α at any Φ, i.e. η(Φ,α) = –η(Φ,–α). The upper left and lower right insets in Fig. 5(a) show temporal profiles of the transverse voltage pulses measured with the excitation beam incident from the air/film interface at an angle of α = 45 deg and polarization azimuths of Φ = 45 and Φ = 135 deg, respectively. One can observe that for both polarizations, the photoresponses are unipolar pulses of opposite polarities and nearly of the same magnitude. It is worth noting that the femtosecond excitation of the nanocomposite film results in the generation of the photocurrent pulses having the duration of several nanoseconds. Since the rise time of the oscilloscope is as short as 875 ps, the response function of the oscilloscope determines the photocurrent rise time. However, the several nanoseconds long decay of the photocurrent pulse may originate from diffusion of the carriers, which were generated in CuSe/Se nanocomposite in the vicinity of both interfaces. A similar effect has been recently observed in PdO polycrystalline films [41] that showed nanosecond scale decay of the light-induced absorption change.
Fig. 5. Dependences of the conversion efficiency on the polarization plane azimuth angle Φ at the laser pulse energy of Ein = 100 µJ and the incidence angle of 45 deg. The orientation of the polarization plane is depicted at the top of the figure. Insets show waveforms of the transverse photovoltage at Φ = 45 and Φ = 135 deg, respectively. The geometries of the experiments are also shown in the insets. (a) Irradiation from the air side. Dots represent the experimental data and the solid line shows fitting with η(Φ) = –2.23sin2Φ. (b) Irradiation from the substrate side. The measured conversion efficiency values for front and tail pulses in the bipolar photoresponse are represented by blue (1) and red (2) dots. Blue (1) and red (2) solid lines show fitting with ηfront = 0.58sin2Φ and ηtail = –0.12sin2Φ.
The upper right and lower left insets in Fig. 5(b) show temporal profiles of the bipolar photoresponse measured with the excitation beam incident from the substrate side at an angle of α = 45 deg and polarization azimuths of Φ = 45 and Φ = 135 deg, respectively. Figure 6 demonstrates bipolar photoresponse generated in the film irradiated from the substrate side. Figure 6(a) presents temporal profiles of the photovoltage pulses generated at the incident angle of α = 45 deg and several polarization azimuths, while Fig. 6(b) shows the temporal profiles of the normalized on Ufront photoresponses at Φ = 45 deg for several angles of incidence.
Fig. 6. Waveforms of the transverse photoresponse of the CuSe/t-Se nanocomposite film irradiated from the substrate side. (a) The temporal profile of the photovoltage at the incidence angle of 45 deg for several polarization azimuths Φ. The inset shows the geometry of the experiment. (b) Normalized on the maximum value photoresponse for several incident angles at the polarization azimuth of Φ = 45 deg. The inset shows the position of the negative tail pulse with respect to the t0 where Usub(t0) = 0 [see Eqs. (3),(6)–(8)].
Since the photocurrent is a linear function of the incident laser pulse energy at all α and Φ, we characterize the bipolar photoresponse by conversion efficiencies defined for the front (ηfront = Ufront/rEin) and tail (ηtail = Utail/rEin) pulses having amplitudes Ufront and Utail, respectively. Figures 5(b) and 6(a) show that both ηfront and ηtail are proportional to sin 2Φ being odd functions of the angle of incidence α (see Fig. 7). Thus, the observed dependence of the photoresponse on the polarization azimuth and incident angle of the excitation beam is characteristic of the SPGE [2,3,26].
Fig. 7. Incident angle dependences of the conversion efficiencies ηfront (1) and ηtail (2) at the irradiation of the film from the substrate side for the polarization azimuth Φ = 45 deg and laser pulse energy of Ein = 100 µJ. Dots represent the experimental data, blue dotted line and red solid line are guides for the eye.
The SPGE photocurrent is zero if electrons undergo mirror reflection at the interface (see Refs. [2,3]). In our experimental conditions, the refractive indexes of the film and substrate are comparable, however, the roughness of the film/substrate interface is much lower than that of the air/film interface. Since the transmittance of the film at 795 nm is as low as 23.6% (see Fig. 1(c)), one may expect that the amplitude of the front pulse is much bigger than the amplitude of the tail one. As a result, we observe a unipolar pulse, which mainly originates from the air/film interface.
If a light pulse is incident from the substrate side, the intensity of the excitation beam at the film/air interface is more than 3 times lower than that at the substrate/film interface, i.e. the amplitudes of the currents at both interfaces may be comparable. In such a case we may observe the bipolar photoresponse pulse if the decay time of the surface photocurrent at the air/film interface is longer than that at the substrate/film interface.
The above qualitative analysis is illustrated by the simple model assuming that the relaxation time of the photoresponse is much longer than the excitation pulse duration. Specifically, in a semitransparent film, both interfaces give opposite contributions to the SPGE photocurrent. That is, the temporal profiles shown in insets in Figs. 5 and 6 are determined by the interplay of two photocurrents that have opposite polarities (see also Figs. 2 and 3). Since we observe a unipolar pulse when the light beam hits the air/film interface first, one may expect that in this geometry, the current generated at the air/film interface dominates. In contrast, the bipolar pulse observed when the excitation beam hits the substrate/film interface first indicates that the currents generated at the substrate/film and film/air interfaces are comparable in amplitude and have different decay times.
The photovoltage generated in the film irradiated from the air side can be presented in the following form [3,42]:
Similarly, the photovoltage of the excitation beam incident on the film from the substrate side can be presented in the following form:
This model allows us to present the strengths of the photoresponses at air/film and film/substrate (Kaf and Kfs, respectively) interfaces in terms of the amplitudes Uair(t = 0) and Usub(t = 0):
One can observe from Figs. 5(a) and 6(a) that Uair(t = 0) = 10.46 mV, Usub(t = 0) = 2.96 mV at the incident angle α = 45 deg and polarization azimuth Φ = 45 deg. By taking into account that at α = 45 deg and Φ = 45 deg the film transmittance is T = 0.217, from Eqs. (3) and (4) one can obtain Kaf = 12.1 mV, Kfs = 6.17 mV and Kfs/TKaf = 2.17.
Equation (3) predicts that the Usub(t = 0) = 0 at
Fig. 8. Normalized on the maximum value transverse photoresponse of the CuSe/t-Se nanocomposite film irradiated from the substrate side at α = 45 deg, Φ = 45 deg. The characteristic times t0, ttail and Δt, and calculated τfs and τaf are also shown.
Since both Kfs and Kaf determine the conversion efficiency and are proportional to sin 2Φ, the time intervals ttail and t0 do not depend on the polarization azimuth of the excitation beam. Such a conclusion corresponds well to the experimental results shown in Fig. 6(a). One can observe from Eqs. (6) and (7) that
That is, the position of the tail pulse with respect to t0 does not depend on the surface nonlinearity and is determined by the scattering times τaf and τfs. One can observe from the inset in Fig. 6(b) that in our experiment, Δt = ttail – t0 shows a weak dependence on the angle of incidence, i.e. in the whole measurement range Δt = 6.7 ± 0.7 ns.
From Eqs. (7) and (8) one can present τaf and τfs in terms of the t0 and Δt = ttail – t0 as follows:
Since at α = 45 deg, Φ = 45 deg, A = [ln(Kfs/TKaf)]–1 = 1.29, t0 = 9.5 ns and Δt = 6.4 ns (see Fig. 8), Eqs. (9) and (10) give τfs = 5.0 ns and τaf = 7.6 ns. This finding makes SPGE an attractive tool in the study of the dielectric/semiconductor interface.
4. Conclusion
In conclusion, we discovered that the temporal characteristics of photocurrents generated at the air/nanocomposite and glass/nanocomposite interfaces are essentially different from one another. When the excitation femtosecond pulse hits the air/nanocomposite interface, the photoresponse is a unipolar nanosecond pulse. In contrast, when the semi transparent film is irradiated from the glass side, the bipolar nanosecond pulse is generated. The developed model along with an extensive experimental investigation of the polarization sensitivity allows us to conclude that the SPGE dominates the photoresponse of the semitransparent CuSe/t-Se nanocomposite film. However, when the film is irradiated from the substrate side, the interplay of the SPGE photocurrents at the substrate/film and air/film interfaces may manifest itself as a change in the temporal profile of the photoresponse pulse, which may become bipolar. Nevertheless, in both geometries, the photocurrent is an odd function of the angle of incidence and polarization azimuth of the excitation laser beam as it is predicted by the SPGE mechanism. The obtained results enable control of the amplitude and temporal profile of the photoresponse by changing the polarization of the excitation laser beam and its orientation with respect to the CuSe/t-Se film.
Funding
Ministry of Education and Science of the Russian Federation (АААА-А19-119021890083-0); Russian Foundation for Basic Research (19-02-00112); Academy of Finland (298298, 320166, 323053); H2020 Marie Skłodowska-Curie Actions (823728, DiSetCom).
Acknowledgments
We are grateful to Dr. Pertti Paakkonen for ellipsometric measurements of the complex refractive index of the CuSe/Se film. A part of this study was performed using equipment of the UdmFRC UB RAS Shared Use Center “Center of Physical and Physicochemical Methods of Analysis and Study of the Properties and Surface Characteristics of Nanostructures, Materials, and Products”.
Disclosures
The authors declare no conflicts of interest.
References
1. M. M. Glazov and S. D. Ganichev, “High frequency electric field induced nonlinear effects in graphene,” Phys. Rep. 535(3), 101–138 (2014). [CrossRef]
2. V. L. Gurevich and R. Laiho, “Photomagnetism of metals. First observation of dependence on polarization of light,” Phys. Solid State 42(10), 1807–1812 (2000). [CrossRef]
3. G. M. Mikheev, A. S. Saushin, V. M. Styapshin, and Y. P. Svirko, “Interplay of the photon drag and the surface photogalvanic effects in the metal-semiconductor nanocomposite,” Sci. Rep. 8(1), 8644 (2018). [CrossRef]
4. A. F. Gibson, M. F. Kimmitt, and A. C. Walker, “Photon drag in germanium,” Appl. Phys. Lett. 17(2), 75–77 (1970). [CrossRef]
5. V. M. Kovalev, A. E. Miroshnichenko, and I. G. Savenko, “Photon drag of a Bose-Einstein condensate,” Phys. Rev. B 98(16), 165405 (2018). [CrossRef]
6. B. P. Zakharchenya, D. N. Mirlin, V. I. Perel’, and I. I. Reshina, “Spectrum and polarization of hot-electron photoluminescence in semiconductors,” Sov. Phys. Usp. 25(3), 143–166 (1982). [CrossRef]
7. V. L. Al’perovich, V. I. Belinicher, V. N. Novikov, and A. S. Terekhov, “Surface photovoltaic effect in gallium arsenide,” JETP Lett. 31, 546–549 (1980).
8. L. I. Magarill and V. M. Entin, “Surface photogalvanic effect in metals,” Sov. Phys. JETP 54, 531–535 (1981).
9. G. M. Mikheev, V. Y. Kogai, T. N. Mogileva, K. G. Mikheev, A. S. Saushin, and Y. P. Svirko, “Photon helicity driven surface photocurrent in CuSe films,” Appl. Phys. Lett. 115(6), 061101 (2019). [CrossRef]
10. V. L. Gurevich and R. Laiho, “Photomagnetism of metals: Microscopic theory of the photoinduced surface current,” Phys. Rev. B 48(11), 8307–8316 (1993). [CrossRef]
11. A. S. Vengurlekar and T. Ishihara, “Surface plasmon enhanced photon drag in metal films,” Appl. Phys. Lett. 87(9), 091118 (2005). [CrossRef]
12. J. Karch, P. Olbrich, M. Schmalzbauer, C. Zoth, C. Brinsteiner, M. Fehrenbacher, U. Wurstbauer, M. M. Glazov, S. A. Tarasenko, E. L. Ivchenko, D. Weiss, J. Eroms, R. Yakimova, S. Lara-Avila, S. Kubatkin, and S. D. Ganichev, “Dynamic Hall effect driven by circularly polarized light in a graphene layer,” Phys. Rev. Lett. 105(22), 227402 (2010). [CrossRef]
13. H. Kurosawa and T. Ishihara, “Surface plasmon drag effect in a dielectrically modulated metallic thin film,” Opt. Express 20(2), 1561–1574 (2012). [CrossRef]
14. N. Noginova, V. Rono, F. J. Bezares, and J. D. Caldwell, “Plasmon drag effect in metal nanostructures,” New J. Phys. 15(11), 113061 (2013). [CrossRef]
15. G. M. Mikheev, A. G. Nasibulin, R. G. Zonov, A. Kaskela, and E. I. Kauppinen, “Photon-drag effect in single-walled carbon nanotube films,” Nano Lett. 12(1), 77–83 (2012). [CrossRef]
16. M. Akbari, M. Onoda, and T. Ishihara, “Photo-induced voltage in nano-porous gold thin film,” Opt. Express 23(2), 823–832 (2015). [CrossRef]
17. M. Durach and N. Noginova, “On the nature of the plasmon drag effect,” Phys. Rev. B 93(16), 161406 (2016). [CrossRef]
18. H. Kurosawa, K. Sawada, and S. Ohno, “Photon drag effect due to Berry curvature,” Phys. Rev. Lett. 117(8), 083901 (2016). [CrossRef]
19. G. M. Mikheev, A. S. Saushin, V. V. Vanyukov, K. G. Mikheev, and Y. P. Svirko, “Femtosecond circular photon drag effect in the Ag/Pd nanocomposite,” Nanoscale Res. Lett. 12(1), 39 (2017). [CrossRef]
20. L. Zhu, Y. Huang, Z. Yao, B. Quan, L. Zhang, J. Li, C. Gu, X. Hu, and Z. Ren, “Enhanced polarization-sensitive terahertz emission from vertically grown graphene by a dynamical photon drag effect,” Nanoscale 9(29), 10301–10311 (2017). [CrossRef]
21. J. H. Strait, G. Holland, W. Zhu, C. Zhang, B. R. Ilic, A. Agrawal, D. Pacifici, and H. J. Lezec, “Revisiting the photon-drag effect in metal films,” Phys. Rev. Lett. 123(5), 053903 (2019). [CrossRef]
22. T. Ronurpraful, D. Keene, and N. Noginova, “Plasmon drag effect with sharp polarity switching,” New J. Phys. 22(4), 043002 (2020). [CrossRef]
23. L. I. Magarill and M. V. Entin, “Photogalvanic effect in films,” Sov. Phys. Sol. State 21, 743–748 (1979).
24. V. L. Al’perovich, A. O. Minaev, and A. S. Terekhov, “Ballistic electron transport through epitaxial GaAs films in a magnetically induced surface photocurrent,” JETP Lett. 49, 702–705 (1989).
25. G. M. Mikheev, V. Y. Kogai, K. G. Mikheev, T. N. Mogileva, A. S. Saushin, and Y. P. Svirko, “Polarization-sensitive photoresponse of the CuSe/Se nanocomposite prepared by vacuum thermal deposition,” Mater. Today Commun. 21, 100656 (2019). [CrossRef]
26. G. M. Mikheev, V. Y. Kogai, R. G. Zonov, K. G. Mikheev, T. N. Mogileva, and Y. P. Svirko, “Generation of a polarization sensitive photocurrent in a CuSe/Se nanocomposite thin film,” JETP Lett. 109(11), 704–709 (2019). [CrossRef]
27. T. P. Vinod, X. Jin, and J. Kim, “Hexagonal nanoplatelets of CuSe synthesized through facile solution phase reaction,” Mater. Res. Bull. 46(3), 340–344 (2011). [CrossRef]
28. G. B. Sakr, I. S. Yahia, M. Fadel, S. S. Fouad, and N. Romčević, “Optical spectroscopy, optical conductivity, dielectric properties and new methods for determining the gap states of CuSe thin films,” J. Alloys Compd. 507(2), 557–562 (2010). [CrossRef]
29. S. Sonia, P. S. Kumar, D. Mangalaraj, N. Ponpandian, and C. Viswanathan, “Influence of growth and photocatalytic properties of copper selenide (CuSe) nanoparticles using reflux condensation method,” Appl. Surf. Sci. 283, 802–807 (2013). [CrossRef]
30. A. Ghosh, C. Kulsi, D. Banerjee, and A. Mondal, “Galvanic synthesis of Cu2−xSe thin films and their photocatalytic and thermoelectric properties,” Appl. Surf. Sci. 369, 525–534 (2016). [CrossRef]
31. S. C. Singh, Y. Peng, J. Rutledge, and C. Guo, “Photothermal and joule-heating-induced negative-photoconductivity-based ultraresponsive and near-zero-biased copper selenide photodetectors,” ACS Appl. Electron. Mater. 1(7), 1169–1178 (2019). [CrossRef]
32. M. S. Khoshkhoo, J. F. L. Lox, A. Koitzsch, H. Lesny, Y. Joseph, V. Lesnyak, and A. Eychmuller, “Highly conductive copper selenide nanocrystal thin films for advanced electronics,” ACS Appl. Electron. Mater. 1(8), 1560–1569 (2019). [CrossRef]
33. R. A. Young, ““Introduction to the Rietveld method,” in The Rietveld MethodR. A. Young, ed. (Oxford University), 1–38 (1993).
34. DifracPlus Topas: Topas 4.2 Technical Reference (Bruker AXS, 2009).
35. Y.-Q. Liu, H.-D. Wu, Y. Zhao, and G.-B. Pan, “Metal ions mediated morphology and phase transformation of chalcogenide semiconductor: from CuClSe2 microribbon to CuSe nanosheet,” Langmuir 31(17), 4958–4963 (2015). [CrossRef]
36. V. L. Al’perovich, V. I. Belinicher, V. N. Novikov, and A. S. Terekhov, “Surface photovoltaic effect in solids. Theory and experiment for interband transitions in gallium arsenide,” Sov. Phys. JETP 53, 1201–1208 (1981).
37. C. Lee, Y. K. Lee, Y. Park, and J. Y. Park, “Polarization effect of hot electrons in tandem-structured plasmonic nanodiode,” ACS Photonics 5(9), 3499–3506 (2018). [CrossRef]
38. S. Riazimehr, S. Kataria, J. M. Gonzalez-Medina, S. Wagner, M. Shaygan, S. Suckow, F. G. Ruiz, O. Engstro, A. Godoy, and M. C. Lemme, “High responsivity and quantum efficiency of graphene/silicon photodiodes achieved by interdigitating schottky and gated regions,” ACS Photonics 6(1), 107–115 (2019). [CrossRef]
39. S. M. A. Mirzaee, O. Lebel, and J.-M. Nunzi, “A simple unbiased hot-electron polarization-sensitive near- infrared photo-detector,” ACS Appl. Mater. Interfaces 10(14), 11862–11871 (2018). [CrossRef]
40. S. Chen, R. Cao, X. Chen, Q. Wu, Y. Zeng, S. Gao, and Z. Guo, “Anisotropic plasmonic nanostructure induced polarization photoresponse for MoS2-based photodetector,” Adv. Mater. Interfaces 7, 1902179 (2020). [CrossRef]
41. V. Liakhovetskyi, A. Brodyn, V. Rudenko, M. Brodyn, and V. Styopkin, “High refractive nonlinearity of PdO films under femtosecond 800 nm laser pulses,” J. Appl. Phys. 128(1), 013108 (2020). [CrossRef]
42. E. L. Ivchenko, Optical Spectroscopy of Semiconductor Nanostructures (Springer, 2004).
