Structural, optical and electrical properties of nitrogen and lithium doped ZnO

Abstract

Zinc oxide (ZnO) is a wide band gap (Eg = 3.3 eV at 300 K) semiconductor with large exciton binding energy at room temperature (~ 60 meV). As-grown ZnO is always n-type though p-type doping is indispensable to fabricate opto-electronic devices. This thesis contains studies on p-type doping in ZnO by lithium (Li) and nitrogen (N). After chemical synthesis of doped and as-prepared ZnO, the films were deposited by pulsed laser deposition and characterized by structural, optical and electrical techniques. It was observed from the x-ray diffraction (XRD) and Raman spectroscopy that Li had substituted Zn in ZnO lattice. The change in a- and c-parameter with Li incorporation was found to be due to lattice strain. It was also observed from photoluminescence (PL) measurements that no deep level was formed prohibiting p-type conductivity.