Abstract
Deposition of thin (~9 Å) In0.5Ga0.5As layer on the GaAs(100) surface using MOCVD results in a formation of nanoscale islands of two types: pyramid-like with a 200 Å × 200 Å square base and a height of about 80 Å and disk-like with a characteristic size of 300–500 Å and a height of 5–10 monolayer (Fig, la). Double heterojunction GaAs-AlGaAs injection lasers were grown with InGaAs islands introduced in the active region (Fig. 1b). The photoluminescence (PL) spectrum of the laser structure with etched off contact layer is shown in Fig. 1c. Maximum of the electroluminescence corresponds to radiative recombination via disk-like islands (line I). Lasing via quantum islands is observed with ultrahigh temperature stability of the threshold current density up to 220 K (see inset in Fig. 2). Characteristic temperature measured in the temperature range 80–220 K is equal to 530 K. Increase in the operation temperature above 220 K results in threshold current density increase. This effect can be attributed to the thermal evaporation of carriers from quantum islands to the GaAs continuum.1 Threshold current density of ~150 A/cm2 was measured at 300 K (L = 1780 μ). Decrease in the resonator length down to L < 250 mkm result in saturation of the gain for transitions via quantum island states and the lasing starts via the wetting layer (WL) states at energy of ~1.38 eV. At high injection current densities (5 kA/cm2) and short cavity lengths (L < 250 mkm), lasing occurs in a wide spectral range (1.31–1.39 eV) simultaneously (Fig. 3).
© 1996 Optical Society of America
PDF ArticleMore Like This
M. Grundmann, N.N. Ledentsov, F. Heinrichsdorff, M.-H. Mao, D. Bimberg, V.M. Ustinov, P.S. Kop’ev, Zh.I. Alferov, and J.A. Lott
RMB5 Radiative Processes and Dephasing in Semiconductors (RPDS) 1998
G. Wang, C.-K. sun, J.E. Bowers, G. Medeiro-Ribeiro, and P.M. Petroff
ThQ5 International Quantum Electronics Conference (IQEC) 1996
Katsuaki Tanabe, Katsuyuki Watanabe, and Yasuhiko Arakawa
P2.15 European Conference and Exhibition on Optical Communication (ECOC) 2012