The effect of adsorbed impurities on the surface properties of GaAs and the characteristics of electroluminescent p-n junctions

The effect of adsorbed copper and gold on the band bending, the steady-state photoconductivity, and the field-effect mobility in n-type GaA s has been studied. The light and electrical characteristics of electroluminescent p-n junctions have also been studied. It is shown that doping the GaA s surface with Cu and Au leads to an increase of the depleting band bending and to a decrease in the field-effect mobility. Copper, adsorbed at the surface of slices before diffusion, leads to a reduction of the radiative intensity of the p-junctions prepared on GaA s with an electron concentration of 1–6·10¹⁷ cm^–3, to a decrease in the cutoff voltage, and to an increase in the differential resistance of the forward branch of the volt-ampere characteristics. It is proposed that in the region of the experimental current (5·10^–2-10^–2) mA the presence of Cu in the electroluminescent p-n junctions leads not to a change in the injection mechanism but to an increase in the series resistance of the p-n junction.Translated from Izvestiya VUZ. Fizika, No. 12, pp. 72–77, December, 1973.