Low Temperature Chemical Vapor Deposition of Cuprous Oxide Thin Films Using a Copper(I) Amidinate Precursor

Cuprous oxide (Cu2O) thin films were grown by chemical vapor deposition (CVD) using precursors (N,N′- di-sec-butylacetamidinato)copper(I) and degassed water at low substrate temperatures of 125–225 °C. Despite being a widely studied material, vapor deposition of Cu2O faces numerous challenges in avoiding material agglomeration, in obtaining high phase purity, and in limiting the process temperature to below 200 °C for temperature sensitive applications. We deposited pinhole-free single-phase oxide films that exhibit Hall mobilities up to 17 cm2 V–1 s–1 and wide band gaps exceeding 2.6 eV that are free from contaminants such as nitrogen, carbon, and cupric oxide (CuO). With good control of growth parameters (source temperature, substrate temperature, and flow rate of carrier gas, etc.), the film morphologies could be tuned to achieve either smooth, pinhole-free coatings or highly crystalline thin films with rough surfaces that are suitable for applications to solar cells.