Photoluminescence of wurtzite ZnO under hydrostatic pressure

Photoluminescence (PL) spectra of single-crystal ZnO bulk under hydrostatic pressure are studied using the diamond-anvil-cell technique at room temperature. The PL spectrum of ZnO single crystal taken at atmospheric pressure was dominated by a strong near-band-edge exciton emission. The emission line was found to shift towards higher energy with increasing applied pressure. By examining the pressure-dependent PL spectral features, the pressure coefficient of the direct Γ band gap of the wurtzite ZnO was determined. The hydrostatic deformation potential of the band gap has also been deduced from the experimental results.