Band-to-band auger recombination in indirect gap semiconductors

Abstract

Electron–hole pairs in semiconductors may recombine through an Auger process. The theory for this process was worked out by Beattie and Landsberg, for a semiconductor with a simple and direct band structure. They found that the conservation laws for energy and crystal momentum lead to a threshold energy for this type of recombination. In the present paper it is shown that an Auger process may equally well take place in an indirect gap semiconductor, without participation of phonons, and that the activation energy, depending on the band structure, may be very low and even accidentally zero. A survey of available band data for silicon and germanium shows that for both these materials the band structure is favourable for an Auger process with low threshold energy. A perturbational approach is applied for calculating the transition rates for silicon and germanium. The results are compared with recent experimental data.

Auger lifetimes for excitons bound to neutral donors and acceptors in Si

“…Jt was found in the case of band-band Auger recombination a t high carrier concentration in Si, that the Auger coefficient for the e-e-h process and the e-h-1.1 process have the same order of magnitude and are practically independent of temperature [ 191. Theoretical considerations predict that the phononless e-h-h process should be much more improbable than the e-e-h process and one should observe a strong temperature dependence of the lifetime [20], whereas a calculation of the phonon-assisted Auger recombination in the case of Ge led to the result of a nearly temperature independent Auger probability [21]. So it seems to be established that the band-band Auger recombination in Si takes place with phonon participation.…”

Group IV Direct Band Gap Photonics: Methods, Challenges, and Opportunities

“…We believe, however, that this is unjustified considering that there is an exponential dependence of the Auger lifetime on the band gap and effective masses (Beattie and Landsberg, 1959;Huldt, 1971;Adams et al, 1980), both being strongly altered in direct band gap Ge. Using the simple exponential dependence derived by Beattie and Landsberg (1959) to scale the experimentally determined Auger recombination coefficient of CGe = 10 −30 cm 6 s −1 (Carroll et al, 2012) via the effective masses and band gaps of direct band gap Ge, an Auger coefficient of the order of 10 is obtained.…”

Physical understanding and technological control of carrier lifetimes in semiconductor materials and devices: A critique of conceptual development, state of the art and applications

“…It must be stressed that the usual carrier density variation of Auger recombination probability as n 2 p or (np 2 ) and the Auger lifetime as n À2 (or p À2 ) is valid for non-degenerate semiconductors with Boltzmann statistics for normal and phonon-assisted Auger processes but not for degenerate semiconductors with Fermi statistics. Auger recombination has been studied by Huldt [38] and Haug [39]. Landsberg and associates have carried out fundamental and pioneering research on Auger recombination.…”

“…The lifetime due to Auger process is observed in such regions of indirect-gap semiconductors or devices where one or more mobile carriers are in excess [32][33][34][35][36][37][38][39][40][41][42][43][44][45][46].…”