Systematic control of carrier concentration and resisitivity in RF sputtered Zinc oxide thin films

Abstract

RF sputtered ZnO and Al:ZnO films are attractive transparent conductive oxides for fabrication of opto-electronic devices. In this paper we present efforts to control carrier concentration and mobility of ZnO/Al:ZnO thin films by controlling deposition parameters (RF power, pressure and substrate temperature. Al:ZnO thin film with resistivity as low as $\rho$ = $3.8\times 10^{-4}$ $\Omega$.cm at deposition temperature of 250{\deg}C has been achieved. Zinc oxide thin film with low resistivity of $\rho$ = $3.7\times 10^{-2}$ $\Omega$.cm and high electron mobility of $30$ $\mathrm{cm^{-2}V^{-1}s^{-1}}$ at deposition temperature of 250{\deg}C with acceptable electronic parameters stability has been obtained.Light transmission of Al:ZnO and ZnO samples deposited on glass at different substrate temperature has been studied. Investigation were made to assess the effect of deposition temperature on the photoluminescence spectra (PL) of ZnO/Al:ZnO sputtered on silicon and glass substrate. The evolution of near band edge (NBE) and deep level emission (DLE) photoluminescence peaks with deposition temperature in ZnO/Al:ZnO sputtered on Silicon and glass substrate have been studied.