Structural and photoluminescence properties of Co-Sputtered p-type Zn-doped ?-Ga2O3 thin films on sapphire substrates

This work discusses the growth characteristics, composition, and photoluminescence properties of Zn-doped Ga2O3 (ZnGaO) films. The idea of doping of Zn divalent cation in ll-Ga2O3 is to modulate the n-type conductivity of ll-Ga2O3 to p-type. Therefore, a series of ZnGaO films with varying Zn contents have been deposited on sapphire substrates using co-sputtering of Ga2O3 and Zn targets at the substrate temperature of 400 degrees C. The X-ray diffraction analysis revealed that divalent Zn dopant is stable up to 8.62% in ZnGaO films. The X-ray photoelectron spectroscopy defined the increasing amount of Zn content in ZnGaO films. The lowest defect formation energy per atom by first-principles calculations indicates that the favourable site of Zn atoms is substitutional Ga tetrahedral site (T-site) in ZnGaO. The photoluminescence (PL) spectra exhibited that the peak emission wavelength of ll-Ga2O3 can be shifted with the inclusion of divalent Zn dopant in Ga2O3 films, which is in accordance with the energy diagram and charge density distribution, indicating the Zn substituted T-site Ga are leading to more defect states, and inducing green luminescence in PL spectra. The ZnGaO films exhibited positive Hall coefficient, which verifies the p-type nature of films. ZnGaO films demonstrate a unique ability to realize ptype characteristics among emerging wide bandgap semiconductors, extending its applications at the forefront of contemporary optoelectronics technologies.

Automated summary

This work discusses the growth, composition, and photoluminescence properties of Zn-doped Ga2O3 (ZnGaO) films. By doping Zn in ll-Ga2O3, the n-type conductivity of ll-Ga2O3 can be modulated to p-type. ZnGaO films with varying Zn contents were deposited on sapphire substrates, and X-ray analysis confirmed the stability of Zn dopant up to 8.62% in ZnGaO films. X-ray photoelectron spectroscopy revealed the increasing Zn content in ZnGaO films. The inclusion of Zn dopant in Ga2O3 films led to a shift in the peak emission wavelength of ll-Ga2O3 in the photoluminescence spectra, indicating the formation of more defect states and inducing green luminescence. The positive Hall coefficient of ZnGaO films verifies their p-type nature.