Auger recombination in PbSnTe‐like semiconductors

Abstract

I n semiconductors with PbSnTe-like band structure the Auger coefficient C, is investigated for most probable eeh transitions taking into account a nonparabolic approximation (NPA). Considering mirror-symmetric hyperbolic bands, singularities in the so-called "activation energy" appear which are removed if deviations from the hyperbolicity are included. At high temperatures T I the value of C , in NPA has the same order of magnitude as the value Czm proposed by Emtage and is nearly independent of temperature; if TI < 77 K the value of C, strongly decreases and differs by orders of magnitude from C:". The obtained results are compared with experimental data.Der Augerkoeffizient C , fur Halbleiter mit PbSnTe-iihnlicher Bandstruktur wird unter Beriicksichtigung von deren Nichtparabolizitiit (NPA) fur die statistisoh wahrscheinlichsten eeh Prozesse untersucht. Setzt man spiegelsymmetrische hyperbolische Biinder voraus, treten Singularitiiten in der sogenannten ,,Aktivierungsenergie" auf, die bei nichthyperbolischen Biindern verschwinden. Fur hohe Temperaturen 2' 1 liegt der Wert von C, in der gleichen GroSenordnung wie der von Emtage vorgeschlagene ( 7 : " und ist ebenfalls schwach temperaturabhiingig; fiir TI < 77 K nimmt C, stark ab und unterscheidet sich um einige GroSenordnungen von C:". Die erhaltenen Werte werden mit experimentellen Ergebnissen verglichen.

Auger recombination dynamics of lead salts under picosecond free-electron-laser excitation

“…theoretical calculations for nonparabolic, nonspherical energy bands in the non-degenerate limit for the excited carrier concentration. 2 Good agreement is also obtained with the room-temperature value for C reported previously, and we confirm the earlier result that for temperatures below 200 K and carrier densities above the threshold for stimulated emission, stimulated recombination represents the most efficient recombination mechanism. 6 We have determined the threshold carrier concentration for stimulated emission over the same temperature range, 30-300 K, and this occurs at carrier concentrations somewhat lower than would be the case for bulk materials with the Kane band structure.…”

“…Excellent agreement between theory and experiment is obtained with the Auger process for intervalley scattering in the approximation of nondegenerate statistics, but it is clearly essential to include a realistic nonparabolic band structure. 2 The difference between the parabolic and nonparabolic approximations is most clearly seen in the lowtemperature regime where the Auger coefficient drops markedly between 77 and 30 K. , which is some four times greater than achieved in the earlier experiments. 13,20 One other clear difference between the two systems is in the dependence of C on temperature.…”

“…The sophistication of a three-beam pump-probe experimental technique described below has enabled an analysis of the decay at times longer than 100 ps in terms of the nonparabolic anisotropic band structure of the lead salts, to give the Auger coefficient C qualitatively over a wide temperature range 30-300 K. The results are in good agreement with theory for nonparabolic, anisotropic bands 11,12 and nondegenerate statistics, 2 and confirm that the original parabolic band calculations 1 underestimated the measured lifetime by more than an order of magnitude. [2][3][4]6 Finally the Auger results for the lead salts are compared with earlier measurements taken at FELIX ͑Ref. 13͒ for Hg 1Ϫx Cd x Te of a composition such that the band gap for the two semiconductors is the same at Tϭ100 K. 13 It is found that C for PbSe is between one and two orders of magnitude lower than for Hg 1Ϫx Cd x Te over the whole temperature range for comparable values of the band gap.…”

“…A particular feature of this system-i.e., their near ''mirror'' conduction and valence bands-has been cited as potentially leading to much smaller Auger scattering rates than found in III-V material systems. However, theory predicts that there may nevertheless still remain a substantial contribution to this unwanted recombination process through intervalley scattering, [1][2][3][4] although later theories, [2][3][4] including more realistic band-structure pictures, suggest that this should not be as serious as originally predicted. 1 Understanding accurately how the recombination processes change with carrier density is important for emission devices which operate far from equilibrium, and in particular in the continuing quest for the development of compact MIR room-temperature lasers.…”

Study on the Theoretical Limitation of the Mid-Infrared PbSe N&lt;sup&gt;+&lt;/sup&gt;-P Junction Detectors at High Operating Temperature

“…It is well known that Auger coefficient in IV-VI semiconductors [5] [6] [7] is about an order of magnitude lower than those in Sb-based type-II QWs, [8] [9] [10] which are in turn significantly suppressed relative to other III-V and II-VI semiconductors such as MCT [11] [12] for the same waveleng. Such low Auger recombination should result in superior device performance such as high detectivity for detectors at a high operating temperature.…”