Coexistence of room-temperature negative differential resistance, negative photoconductivity modulated by UV light intensity and optical switching in Cu/Ni:ZnO/InGa structure

Abstract Cu/Ni:ZnO/InGa structure has been fabricated by depositing the chemically synthesized Ni:ZnO nanoparticles on glass substrate. The device shows a negative differential resistance (NDR) effect and negative photoconductivity (NPC) at room temperature. The presence of NDR is attributed to the electrons trapped/detrapped by interface states at Cu/Ni:ZnO junction. The origin of NPC is understood in term of competition between carriers injection due to the external field and photocarriers due to the external optical signal. Thus, these two effects (NDR and NPC) contribute to the optical switching process found in our device.