Nanojoining and tailoring of current-voltage characteristics of metal-P type semiconductor nanowire heterojunction by femtosecond laser irradiation

Selective engineering of the interface between nanoscale components and the electrical properties of heterojunctions is key to the development of next-generation nanoscale circuit elements. In this paper, we show how laser processing of a metal-P type semiconductor nanoscale heterojunction between Ag and CuO nanowires can be used to control the nature of the electrical contact by reducing the Schottky barrier at the Ag-CuO interface to Ohmic contact. Elimination of the Schottky barriers occurs in response to lattice matching of Ag(111)CuO(111) planes at the interface induced by controlled irradiation with femtosecond (fs) laser pulses. An interdiffusion region with a mixed Ag/CuO composition is also present over a localized area of the interface between the Ag and CuO nanowires after fs laser processing, but both Ag and CuO nanowires remain crystalline away from the heterojunction. In addition, the Ag nanowire becomes totally embedded in the larger CuO nanowire after irradiation. Fabricated nanowire devices from Ag-CuO nanowire heterojunctions transition from a double-Schottky contact configuration prior to laser processing to a rectifying behavior as irradiation time increases. This study illustrates that fs laser processing can be highly effective in the engineering of electrical performance in metal-semiconductor nanoscale heterojunction devices.