Optical and electrical characterization of n-GaAs surfaces passivated by N2–H2 plasma

The passivation of GaAs (1 0 0) surface has been performed by using remote N2–H2 (3% in H2) RF plasma nitridation. The samples, consisting of n-doped GaAs wafers, show photoluminescence enhancement when the nitridation time and exposure to the plasma are in a narrow temporal window, so that a very thin (about 10 Å) GaN layer is deposited on the GaAs surface. Pure N2 nitridation does not provide an efficient passivation, because it results in GaN layers with As and AsNx segregation at the GaN/GaAs interface. Increase of Au–GaAs Schottky barrier with the insertion of GaN interlayer and improvement of current–voltage characteristic have been observed.