KINETICS OF GAAS(100) PASSIVATION IN ACQUEOUS SOLUTIONS OF SODIUM SULFIDE

The change in the intensity of GaAs (100) photoluminescence after surf ace passivation in acqueous solutions of sodium sulfide was studied as a function of the treatment time, temperature, and composition of the sulfide solution. It was shown that as the treatment time in the sulf ide solution is increased, the intensity of the photoluminescence maxi mum increases and then saturates. The saturation time depends on the a lkalinity of the solution and on the concentration of the sulfide ions in it. For a fixed treatment time the intensity of the photoluminesce nce peak increases with the sulfidation temperature. The data from x-r ay photoelectron spectroscopy of the sulfidized surfaces show that Ga- S bonds are present and that the content of arsenic oxides on the semi conductor surface decreases as the sulfidation temperature increases. The increase in the photoluminescence intensity with sulfide passivati on is associated mainly with the decrease in the content of these oxid es. (C) 1995 American Institute of Physics.