The development of an electrochemically robust method for the low-temperature deposition of cuprous oxide (Cu2O) thin films with reliable and conductive p-type characteristics could yield breakthroughs in earth abundant and ecofriendly all oxide-based photoelectronic devices. The incorporation of the group-V element antimony (Sb) in the solution-based electrodeposition process has been investigated. A small amount of Sb (1.2 at%) in the Cu2O resulted in rapid nucleation and coalescence at the initial stage of electrochemical reaction, and finally made the surface morphology smooth in 2D. The growth behavior changed due to Sb addition and produced a strong diffraction intensity, single-domain-like diffraction patterns, and low angle tilt boundaries in the Cu2O:Sb film, implying extremely improved crystallinity. As a result, these films exhibited extraordinary optical transmittance and band-to-band photoluminescence emission as well as higher electrical conductivity. The Cu/Cu2O:Sb Schottky diode showed good rectifying characteristics and more sensible photoresponsibility.