ETCH PIT STUDIES OF GAP LIQUID-PHASE EPITAXIAL LAYERS

In investigations of the influence of defects on the luminescence properties of compound semiconductors, the relative importance of purely structural defects, e. g. , dislocations, vs. imperfections of a chemical or stoichiometric nature, such as impurities, vacancies, etc. , is invariably discussed. Recent photoluminescence studies on GaAs and GaP have shown that dislocations are an important factor only if they are decorated with impurities. For GaP the decorated dislocations only occur when there is also present another type of etch feature called a saucer or S-pit. In the present report further comparisons of dislocations and S-pits are made in GaP material typical of that used in electroluminescent devices made by liquid phase epitaxy (LPE). The etch pit studies on LPE material have been examined in terms of using S-pits as an observable in evaluating the device potential of different LPE layers.