Strained layer optoelectronic devices

Abstract

Auger recombination affect adversely the performance of InGaAs based visible lasers and other long wavelength lasers. Auger processes are intrinsic and can not be suppressed by improving the quality and purity of the sample. Early predictions that strain can suppress the Auger recombination and reduce the threshold current were made by Yablonovitch and Kane [51]. In the following years strain played an important role in improving the performance of InGaAs lasers grown on GaAs substrates. Excellent reviews of the subject have been written by Morkog et al.} [12] and by O’Reilly et al.} [42]. At the present time there is a great interest in the study of mid-IR (2 to 5 μm) InGaSb-based lasers. There is a transparency window in the 2-5 μm range in the atmosphere. Therefore mid-IR devices are useful for several applications discussed in section 7.5.6. Detrimental effect of Auger recombination increases as the temperature increases and bandgap decreases. Therefore the harmful effect of Auger recombination is more serious in mid-IR lasers. The mid-IR lasers do not yet operate at room temperature because of the limitation due to Auger recombination. Mid-IR lasers using Sb based III-V semiconductor strained layers have been fabricated and studied recently. In this section we review the theoretical and experimental work that has been done to suppress the Auger recombination in InGAs- and GaSb-based lasers.