The facilities incorporated in a specially designed horizontal SEM system allows the measurement of both steady state intensity and decay features of cathodoluminescence (CL) in terms of photon count. The sample temperature is controlled via a liquid nitrogen finger Deep level CL bands from n-type GaAs were investigated by using above facilities. The measured features were temperature quenching and excitation dependence of the CL intensity as well as the CL transient Sample. I was a n-type MOCVD GaAs layer with sulphur doped After Cr diffusin at 800℃

sample Ⅰ became sample Ⅱ Although both samples had two main CL bands around 1.2 and 1.0 eV

their positions shifted and their behaviors were quite different. In this work

band A peaked at about 1.15 eV from sample I and band A

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peaked at about 1.26 eV from sample I we’re measured. It was found that band A had an approximate single exponential decay behavior and band A

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hada double exponential decay behavior For the purpose of theoretically understanding the experimental results

we developed a complete dynamic analysis of deep level luminescence in heavily doped n-type gallium arsenide

based on two different models ’single level model and double levle model. The former implies that the luminescence originates from a free-to-bound transition

the latter implies a transition between the excited state and the ground state of a deep center. Careful derivation shows that the two models give different behaviors of luminescence intensity and decay time Comparing with the actual experimental results

the double level model is favourable Especially

a possible configurational coordinate figure is given to describe the transition associated with band A

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The conclusion is that the properties of band A and band A

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are completely different Our results support the suggestion that band A is associated with gallium vacancy and band A is caused by chromium atom replacing the vacancy.