Isoelectronic traps in semiconductors (experimental)

Abstract

After a brief description of the essential characteristics of isoelectronic traps, this review is mainly concerned with new experimental information on this important class of luminescence activator centre. Some predictions concerning the likely, most fruitful directions for further research are given. Present understanding of the existence criteria for classical point defect isoelectronic traps suggests that new ones will be hard to find, since the tractible, generally narrow gap semiconductors have been studied quite extensively and only a few of the wider gap III-V and II-VI semiconductors may be considered worthy of the necessary technological effort in materials preparation. However, many complex centres possess the generic properties of isoelectronic traps, the simplest examples being "molecular" centres such as nearest-neighbour donor-acceptor associates. Such centres, particularly those producing deep levels which may dominate the recombination processes, are receiving increasing attention. For technological as well as academic reasons, many of the earliest gains in such investigations are likely to be found in GaP, where a considerable wealth of understanding of optical properties already exists. The current status of knowledge of several such centres in GaP is reviewed here. © 1973.