Increase of Critical Thickness and Optical Emission Range in (InAs)1(GaAs)n Strained Short-Period Superlattices

The critical thickness and optical emission wavelength range of (InAs)1(GaAs) n strained short-period superlattices (SSPSs) grown on GaAs(100) substrates were investigated by reflection high-energy electron diffraction, transmission electron microscopy and photoluminescence (PL). When the (InAs)1(GaAs) n SSPSs were grown at a substrate temperature of 420°C, the critical thickness was increased up to about ten times as large as that of InGaAs alloys except for the (InAs)1(GaAs)1 SSPS. The wavelength range of the PL peak was markedly increased in the (InAs)1(GaAs) n SSPS/GaAs single quantum wells (SQWs), compared with that in the InGaAs/GaAs SQWs. When the (InAs)1(GaAs) n SSPS was grown at 500°C, the longest experimental wavelength was 1.16 µm at room temperature. A wide range of PL peak wavelengths from 0.87 to 1.23 µm can be expected at room temperature in the (InAs)1(GaAs) n SSPSs, if nonradiative recombinations can be reduced with a low temperature growth of 420°C.