The role of dislocations in producing efficient near-bandgap luminescence from silicon

Abstract

Cathodoluminescence is used to investigate the phenomenon of relatively efficient band-to-band luminescence from silicon specimens processed to contain near surface dislocations. Dislocations are produced either by ion implantation and subsequent high-temperature annealing or by mechanical abrasion of specimens having a wide range of doping concentrations. It is found that the luminescence is not directly related to the presence of dislocations and, in some cases, can be enhanced by low temperature annealing. This luminescence behaviour is explained by the effect of competing non-radiative recombination due to impurity deep levels and Auger recombination. The enhancement observed in some specimens is due to gettering of the deep level impurities. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.