Radiative and interfacial recombination in CdTe heterostructures

Abstract

Double heterostructures (DH) were produced consisting of a CdTe film between two wide band gap barriers of CdMgTe alloy. A combined method was developed to quantify radiative and non-radiative recombination rates by examining the dependence of photoluminescence (PL) on both excitation intensity and time. The measured PL characteristics, and the interface state density extracted by modeling, indicate that the radiative efficiency of CdMgTe/CdTe DHs is comparable to that of AlGaAs/GaAs DHs, with interface state densities in the low 1010 cm−2 and carrier lifetimes as long as 240 ns. The radiative recombination coefficient of CdTe is found to be near 10−10 cm3s−1. CdTe film growth on bulk CdTe substrates resulted in a homoepitaxial interface layer with a high non-radiative recombination rate.

Research Update: Relativistic origin of slow electron-hole recombination in hybrid halide perovskite solar cells

“…These are the charge carrier densities relevant for device operation in sunlight. As B is fairly constant below this charge carrier density, we can use Equation (7) to derive a lifetime of order [35][36][37] 130-1300 267 CdTe [38][39][40] 100-5100 195 Si 41,42 0.001-0.01…”

Effect of free-carrier concentration and optical injection on carrier lifetimes in undoped and iodine doped CdMgTe/CdSeTe double heterostructures grown by molecular beam epitaxy

“…2 layers, has been demonstrated in the previous study by Swartz et al [6]. Similarly, studies of CdTe absorber layer passivation by CdMgTe barrier layers are reported in Refs.…”

“…(2) is related to the radiative lifetime. Auger recombination is negligible in CdTe [6] and therefore not included in the above equation.…”

“…[6,7] This improvement in lifetime () was attributed to significant reduction of the interface defect states owing to the presence of the high-quality interface with the CdMgTe barrier layer. [6] Recently, a CdTe/CdMgTe DHs/InSb based solar cell has shown an open circuit voltage over 1 V, which illustrates the potential improvement in solar cell performance when incorporating CdMgTe DH confinement layers. [8] Photoluminescence (PL) is a powerful technique for characterizing carrier dynamics in materials.…”

Study of recombination in CdMgTe/CdTeSe heterostructures using photoluminescence intensity and lifetime measurements with confocal photoluminescence microscopy

“…[14]- [15] Instead of using the ShockleyRead-Hall (SRH) formula for the recombination rate, or treating the interfacial recombination velocity S as a single physical parameter, full trap capture statistics were used. This is because the SRH formula is only valid in the steady state, and because S is in fact not a constant parameter, but is strongly dependent on excitation III.…”