Emission and Excitation Spectra of ZnO:Ga and ZnO:Ga,N Ceramics

TL;DR

This study investigates the spectral properties of ZnO:Ga and ZnO:Ga,N ceramics, revealing their luminescence behaviors, temperature effects, and excitation mechanisms, with implications for optoelectronic applications.

Contribution

It provides new spectral data and analysis of energy transfer mechanisms in ZnO:Ga and ZnO:Ga,N ceramics prepared by hot pressing.

Findings

Edge band at 3.12 eV dominates in ZnO:Ga luminescence.

Wide band at 2.37 eV observed in ZnO:Ga,N, likely due to zinc vacancies.

Edge-band maximum shifts to lower energies upon heating.

Abstract

The spectral characteristics of ZnO:Ga and ZnO:Ga,N ceramics prepared by uniaxial hot pressing have been investigated. At room temperature, the edge (exciton) band at 3.12 eV dominates in the luminescence spectra of ZnO:Ga, while a wide luminescence band at 2.37 eV, which is likely to be due to zinc vacancies, is observed in the spectra of ZnO:Ga,N. Upon heating, the edge band maximum shifts to lower energies and the bandwidth increases. The extrapolated position of the edge-band maximum at zero temperature, Em(0) = 3.367 +/- 0.005 eV, is in agreement with the data for thin zinc oxide films. The luminescence excitation spectra in the range from 3 to 6.5 eV are reported and the mechanism of energy transfer to excitons and luminescence centers is considered.