Nonparabolicity effects on carrier lifetimes in bulk Hg1-xCdxTe alloys and Mid-Infrared 2D Hg1-xCdxTe/CdTe Single Quantum Well Lasers

Abstract

We report on a theoretical study of nonparabolicity (NP) effects on carrier lifetimes in narrow energy bandgap bulk (3D) Hg 1-x Cd x Te ternary alloys and their related 2D Hg 1-x Cd x Te/CdTe Single Quantum Well (SQW) nanostructures for Mid-infrared (MIR) Laser applications. Carrier lifetime (τ) calculations are performed within both the parabolic and the 4-band CB + HH + LH + SO nonparabolic models. We show that NP affects strongly all three main scattering processes: Auger, Schockley-Read-Hall (SRH), and radiative recombination (RR). At 300 K and in mid-Cd contents (0.4 < x < 0.6) 3D Hg 1-x Cd x Te alloys, Auger 1 is shown to be the dominant τ limiting factor. In 2D Hg 1-x Cd x Te/CdTe SQW nanostructures, we show that RR turns out to be the dominant τ limiting process. This strongly reduced influence of Auger1 process in 2D Hg 1-x Cd x Te/CdTe SQW nanostructures is the result of the strong 2D quantum confinement induced amplification of NP effects via much stronger electron (CB) and all three hole (HH, LH, SO) energy subbands interactions and mixing. As a consequence, NP effects are finally shown to significantly improve all main 2D Hg 1-x Cd x Te/CdTe SQW Laser parameters in the MIR λ range with an optimum at x = 0.45 and for wide enough QW with L z ≥ 100 Å. • Nonparabolicity effects on carrier lifetimes in Hg 1-x Cd x Te 3D and 2D MIR Lasers. • Auger scattering processes are dominant at 300 K in 3D Hg 1-x Cd x Te alloys (0.3 < x < 0.6). • Radiative recombination is dominant 300 K in 2D Hg 1-x Cd x Te/CdTe QW (x ≥ 0.40). • NP affects strongly carrier lifetimes, and consequently, all main laser parameters. • NP improves Laser emission wavelength, optical gain and threshold current densities.