Effects of Transition Energy on Intra-Band Photoluminescence of Zinc Oxide (ZnO) Semiconductor under Low injection Level

Getu Endale

doi:10.13189/ujms.2019.070301

Abstract

This paper presents the effects of the transition energies on photoluminescence intensities in Zinc Oxide compound semiconductor due to the intra-band transition of free carriers. The excitation of free carriers from the valence band to conduction band and from different localized state to the conduction band by the illumination of sufficient energy is considered. A theoretical model for minority carrier trapping is also investigated to explain the dependence of the photoluminescence on the trap energy. Variation of photoluminescence intensities along with localized state energy and transition energy is considered at different temperatures. As temperature increases the photoluminescence due to the transition of free electrons from the conduction band to the valence band, from the conduction band to the localized states and from the localized states to the valence band are increasing.

Highlights

For different semiconductor devices, one needs materials with different parameters, like energy band-gap
In the localized state to valence band transition of free carriers, ET − EV is considered as low transition energy for ET below the mid-gap and vice versa
The conduction band to valence band photoluminescence intensity is described only by a single transition energy EC −EV at constant temperature

Summary

Introduction

One needs materials with different parameters, like energy band-gap. By substituting the typical values for energy band gap, capture coefficients, acceptor energy levels and carrier’s concentrations of the zinc oxide semiconductor, the competition between the photoluminescence intensity of different localized states are described.

Results

Conclusion