Abstract

In_xGa_1-xN alloy semiconductors have bandgaps ranging from 0.72eV (x=1.0) to 3.4 eV (x=0) which covers the visible to near-IR wavelength range. Low threshold visible lasers are useful for a number of applications including full color mobile projectors, optical data storage, heads-up displays in automobiles, in medicine and plastic fiber communication. Lasers emitting in the blue and green are generally realized with GaN-based InGaN/GaN quantum wells (QWs) as the gain media [1]. However, there are materials-related issues which compromise the performance characteristics and prevent the epitaxy of quantum wells for lasers emitting at longer wavelengths. GaN nanowires of 60-80nm diameter and relatively free of extended defects, can be grown on (001)Si substrates [2]. In_xGa_1-xN disks, 2-3nm in thickness can be inserted in the GaN nanowires and by varying the alloy composition, the emission from the InGaN disks can be varied over a large wavelength range. The aerial density of the nanowires can be varied in the 10¹⁰ to 10¹¹cm⁻² range. From several experiments, it is now evident that a Volmer-Weber QD is formed in the disk region [3]. Room-temperature photoluminescence from the In_xGa_1-xN disk region have the peak emission wavelength varying from 530nm (x=0.34) to 1.6μm (x=1.0). The dot in nanowire heterostructures can therefore be used to design and fabricate light sources with emission extending from the visible to the near-infrared, a wavelength range that has remained inaccessible with quantum well devices. In particular, a monolithic nanowire diode laser with emission at 1.3μm is important for silicon photonics. The characteristics of visible and 1.2 – 1.3μm dot-in-nanowire edge-emitting diode lasers on (001)Si will be presented.

© 2016 Optical Society of America