LARGE ACTIVATION OF PRASEODYMIUM IN IN0.53GA0.47AS

The electrical properties of Pr-doped In0.53Ga0.47As LPE epitaxial layers have been studied. Layers prepared by adding a small amount of PrO2 to the melt are n-type and they are insensitive to the temperature treatment. p-type epitaxial layers were grown when more than 1 mg of PrO2 per 1 g of In was added to the melt. Annealing at a temperature of 400-degrees-C results in drastic changes of the electrical parameters and influences the photoluminescent spectra of p-layers. Praseodymium can be activated in a thin near-surface layer independently of the protective gas or metal covering. Additional annealing of the activated layers at higher temperatures has no further influence on the parameters. After removing the thin surface layer by chemical etching the previous electrical parameters can be obtained.