Non-radiative recombination via deep states in GaAs

Large variation in the luminescence efficiency of gallium arsenide have been reported which in many cases can be correlated with the growth conditions used to produce the material. Synonymous with the variation in optical performance is a variation of minority carrier lifetime. If the measured values are compared with the radiative lifetime it is apparent that the minority carrier lifetime can approach the radiative lifetime in the case of the highest quality material but is sometimes more than two orders of magnitude smaller. There is strong evidence that this is due to a non-radiative path resulting from recombination via deep states. This paper reviews the available data on the properties of deep states in LPE, MBE, VPE, MOVPE and bulk-grown gallium arsenide. The observed non-radiative components of the lifetime can be accounted for in most LPE and MBE material by intrinsic defects. In VPE, MOVPE and bulk grown material the results are less conclusive but it appears that impurities play an important role in degrading the lifetime of the as-grown material in these cases.