Bandgap Engineering and Oxygen Vacancy Defect Electroactivity Inhibition in Highly Crystalline N-Alloyed Ga₂O₃ Films through Plasma-Enhanced Technology

Abstract

Previous research has shown that the hybridization of N 2p and O 2p orbitals effectively suppresses the electrical activity of oxygen vacancies in oxide semiconductors. However, achieving N-alloyed Ga2O3 films, known as GaON, poses a significant challenge due to nitrogen’s limited solubility in the material. In this study, a new method utilizing plasma-enhanced chemical vapor deposition with high-energy nitrogen plasma was explored to enhance the nitrogen solubility in the material. By adjusting the N2 and O2 carrier gas ratio, we could tune the thin film’s bandgap from 4.64 to 3.25 eV, leading to a reduction in the oxygen vacancy density from 32.89% to 19.87%. GaON-based photodetectors exhibited superior performance compared to that of Ga2O3-based devices, with a lower dark current and a faster photoresponse speed. This investigation presents an innovative approach to achieving high-performance devices based on Ga2O3.

Enhancement of crystalline quality and solar-blind photodetection characteristics of ε-Ga2O3 films by introducing Zn impurity

“…2(a) exhibits the high-resolution Ga 2p core-level spectra of the samples, and the peaks at 1117.4 eV and 1144.2 eV can be attributed to Ga 2p 3/2 and Ga 2p 1/2 , respectively. 30,42,43 After introducing Zn impurities, the Ga 2p 3/2 and Ga 2p 1/2 peaks did not shift, but they widened and weakened in intensity. This may be due to the substitution impurities changing the original state of the Ga atoms in the lattice.…”

Over 5 × 103-Fold Enhancement of Responsivity in Ga2O3-Based Solar Blind Photodetector via Acousto–Photoelectric Coupling

“…Yet, they are still hindered by modest responsivity and detectivity. Several approaches have been proposed to overcome these limitations, such as oxygen vacancy filling, substrate miscut angle treatment, field effect gating, surface plasmonic, band engineering, and photogating . All of these methods have been proven to enhance the responsivity or detectivity by several or a dozen times.…”

Solution-Processed Ga2O3 Films via Thermal Annealing for Solar Blind Ultraviolet Photovoltaic Photodetectors with High Photoresponsivity and Fast Response

“…Gallium oxide (Ga 2 O 3 ), a 4.9–5.2 eV wide-band-gap semiconductor with large near band edge absorption coefficient, high thermodynamic stability, and great chemical stability, is considered to be one of the mainstream materials for fabricating SBUV detectors. – Recently, a variety of methods used to grow Ga 2 O 3 materials have been developed, such as MOCVD, PLD, and magnetron sputtering. – However, these methods require strict processes and costly equipment, which has prevented the large-scale manufacturing and application of Ga 2 O 3 SBUV photodetectors. Of course, the solution-processed films have been widely applied to the preparation of photosensitive layers in Ga 2 O 3 SBUV detectors due to the simple process, low cost, and large-area growth, but most reported SBUV detectors based on this kind of films tend to exhibit low photoresponsivity and slow response. – Regarding this situation, it has been confirmed that some unintentional doping defects, such as oxygen vacancies, carbon (C) impurities, hydrogen (H) impurities, etc., are easily formed in the solution-processed Ga 2 O 3 films due to the extremely low formation energy. – These impurity defects that are prone to becoming carrier capture centers will be important factors attenuating the photoresponsivity and response speed.…”