The bulk generation-recombination processes and the carrier lifetime in mid-wave infrared and long-wave infrared liquid nitrogen cooled HgCdTe alloys

Abstract

Comprehensive study of the bulk generation-recombination mechanisms and the carrier lifetime in long wavelength and mid wavelength infrared indium-doped as well as arsenic- and mercury vacancies-doped HgCdTe ternary alloys at liquid nitrogen temperature has been done. The excess minority carrier lifetime in HgCdTe materials has been calculated by solving the set of non-linear transport equations under conditions of small deviation from equilibrium. The results of numerical calculations of the carrier lifetime determined by the Auger 1, Auger 7, and Shockley-Read-Hall mechanisms related to mercury vacancies have been compared with experimental data available in the literature. We re-examine the carrier lifetime, including the impact of the electrical screening on Coulomb interaction of carriers in the Auger process to explain certain inconsistency between theoretical prediction and experimental data especially in highly doped p-type HgCdTe material. Moreover, the marginal significance of the interband radiative recombination has been indicated.

Engineering the Bandgap of Unipolar HgCdTe-Based nBn Infrared Photodetectors

“…The dark current calculations include thermal generation mechanisms, Auger 1, Auger 7, and SRH through metal-site vacancies and dislocation related centers. 25 The metal-site vacancy concentration was assumed to be N T = 1 9 10 13 cm À3 with an ionization energy 0.75E g above the valence band edge, and carrier capture cross-sections of r n = r p = 5 9 10 À16 cm 2 . The bulk dislocations density was assumed to be G DIS = 1 9 10 5 cm À2 , with the mean energy of the dislocation band at 0.32E g above the valence band edge, and carrier cross sections equal to r n = r p = 5 9 10 À15 cm 2 .…”

Carrier Recombination, Long‐Wavelength Photoluminescence, and Stimulated Emission in HgCdTe Quantum Well Heterostructures

“…Carrier recombination in Hg 1− x Cd x Te‐based structures was intensively studied, but mainly in bulk epilayers in regard to their use for IR detectors. There are fewer studies of recombination in narrow gap QWs, especially under intense optical excitation, which is typical for lasers.…”

Investigation of possibility of VLWIR lasing in HgCdTe based heterostructures

“…carrier lifetimes increase with the bandgap indicates that recombination is non-radiative. Review of literature data suggests that the dominating mechanism of carrier recombination is Shockley-Read-Hall (SRH) process [9][10][11]. However, according to recent calculation of carrier recombination rates [11] lifetime of 9.2 µs measured in our bulk epilayer (x = 0.22) practically coincides with the calculated radiative lifetime for n-doped (5×10 14 cm -3…”

“…One can see that PC decay time grows with x up to ~ 10 µs at x = 0.22 and then slightly decreases. The radiative lifetime is known to decrease with the bandgap [9]; hence, such behavior, i.e. carrier lifetimes increase with the bandgap indicates that recombination is non-radiative.…”

“…Firstly, calculations of recombination rates that exploit the full band structure obtained in hybrid pseudopotential tight-binding Hamiltonian model predict longer Auger time than those calculated with widely used analytical expressions [11]. Secondly, at high carrier densities Auger recombination rates are affected by Coulomb screening that should also increase the Auger recombination time [9]. Though at rather high temperature as 100K the Auger recombination lifetime is of the same order of magnitude as spontaneous radiative recombination time according to [11] somewhat of Auger mitigation is indirectly confirmed by our experiments as well.…”