Surface Passivation of In0.52Al0.48As Using (NH₄)₂Sxand P₂S₅/(NH₄)₂S

(NH 4 ) 2 S x and P 2 S 5 /(NH 4 ) 2 S treatments were applied on In 0.52 Al 0.48 As surfaces. From X-ray photoelectron spectroscopy measurements, residual sulful atoms on the surface were found to form In–S, Al–S, and As–S bonds. The performance of Schottky diodes was improved by (NH 4 ) 2 S x and P 2 S 5 /(NH 4 ) 2 S treatments in terms of the reverse leakage current and barrier height. In addition, the advantage of using P 2 S 5 /(NH 4 ) 2 S was revealed compared with (NH 4 ) 2 S x .