Role of native defects on the opto-electronic properties of p-type ZnO synthesized during the most straightforward method: only water

Abstract

The influence of predominant native defects in forming ZnO with p-type conductivity is discussed in this work when the semiconductor is synthesized only in water. The semiconductor was prepared by dissolving a Zn-salt in deionized water at 80 °C. The powders were thermally treated at 400 °C in an air atmosphere to obtain well-defined crystalline ZnO. XRD, SEM, EDS, Raman spectroscopy, diffuse reflectance, photoluminescence, and Seebeck effect techniques were used to characterize the synthesized material. The results showed a well-crystalline semiconductor in wurtzite phase. The crystal-oriented growth was the (002) plane. The sample morphology was formed by highly ordered sticks-like. The optoelectronic characterization showed that the synthesized ZnO had a lower band gap than that reported in the literature. It was related to deep energy levels corresponding to oxygen interstitials as the predominant native defects. Raman, EPR, and photoluminescence spectra analysis corroborated the existence of native defects in the crystalline structure. The p-type conductivity of the sample was determined by Seebeck coefficient analysis. A synthesis reaction mechanism involving the formation of oxygen interstitials was proposed in this work. Understanding the effects of native defects in wide band gap semiconductors is necessary to design new materials for sensors or energy conversion applications.

Advanced NH3 Detection by 1D Nanostructured La:ZnO Sensors with Novel Intrinsic p–n Shifting and Ultrahigh Baseline Stability

“…This observation suggests a p–n shifting or a change in the conductivity type of the synthesized materials from p-type to n-type. It can occur due to the presence of impurities or defects in the material, which can act as donor/acceptor states and change the majority carrier type . Indeed, the observed shift can be typically associated with a change in the dominant charge carriers from holes (p-type) to electrons (n-type).…”

“…It can occur due to the presence of impurities or defects in the material, which can act as donor/acceptor states and change the majority carrier type. 67 Indeed, the observed shift can be typically associated with a change in the dominant charge carriers from holes (ptype) to electrons (n-type). This change in the dominant carrier type can result from the ionization of shallow acceptor or donor states, respectively, as the temperature increases (see the p−n Shifting and Gas Detection Mechanisms section below for an in-depth illustration).…”

Enhanced Conversion Efficiency in MAPbI3 Perovskite Solar Cells through Parameters Optimization via SCAPS-1D Simulation

“…With its wide bandgap and significant exciton binding energy, ZnO is considered one of the most interesting ETL materials [22]. In particular, there has been active research in doping with various other materials to create p-type ZnO [23,24]. However, a reliable p-type ZnO has not yet been reported [25].…”

Sol–Gel Synthesis of ZnO:Li Thin Films: Impact of Annealing on Structural and Optical Properties

“…Undoped ZnO films exhibit n-type conductivity as a consequence of deviation from their stoichiometry and of the presence of native donor defects, such as zinc interstitial (Zn i ) and oxygen vacancy (V 0 ) [19]. For different applications, such as p-n junction-based devices or bipolar device applications, it is necessary to obtain stable p-type oxide semiconductors [19,20]. There are two ways of inducing p-type conductivity in ZnO: one is doping with group I elements (Li, Na, K) at the Zn site; the other is substitution at the O site by group V elements (N, P, Sb) [19].…”