Self-compensation reduction as first step of p-type ZnO synthesis

In this work, we used a new strategy, based on the reduction of self-compensation, to synthesize p-type ZnO thin films. This new protocol is based on the control of intrinsic defects especially the vacancies and the interstitials of both zinc and oxygen networks. It consists of using zinc nitrate as a precursor and varying its concentration on the one hand, and the addition of acetic acid on the other. Hall Effect measurements have shown a decrease in electron concentration as the nitrate concentration increases. A concrete transition in the conductivity of ZnO from n-type to p-type has been observed for concentration around 0,4M. Thermal Analyses (DTA-TGA), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), UV-visible spectrophotometry were used to study the structural, morphological and optical properties of the synthesized layers. All these measures confirm the appearance of a change in behavior when nitrate concentration is approaching 0,4M. This transition in conductivity-type in ZnO layers has been linked to a significant increase in the oxygen content as confirmed by an EDX analysis during films growth. The growth of p-type ZnO films based on zinc nitrate can potentially lead to the development of new transparent devices applicable in optoelectronics and photovoltaic fields.