Thermal annealing effect on β-Ga₂ O₃ thin film solar blind photodetector heteroepitaxially grown on sapphire substrate

Abstract

This paper presents the effect of thermal annealing on β‐Ga2O3 thin film solar‐blind (SB) photodetector (PD) synthesized on c‐plane sapphire substrates by a low pressure chemical vapor deposition (LPCVD). The thin films were synthesized using high purity gallium (Ga) and oxygen (O2) as source precursors. The annealing was performed ex situ the under the oxygen atmosphere, which helped to reduce oxygen or oxygen‐related vacancies in the thin film. Metal/semiconductor/metal (MSM) type photodetectors were fabricated using both the as‐grown and annealed films. The PDs fabricated on the annealed films had lower dark current, higher photoresponse and improved rejection ratio (R250/R370 and R250/R405) compared to the ones fabricated on the as‐grown films. These improved PD performances are due to the significant reduction of the photo‐generated carriers trapped by oxygen or oxygen‐related vacancies.

LPCVD homoepitaxy of Si doped β-Ga2O3 thin films on (010) and (001) substrates

“…1 It exhibits high transparency in the deep UV and visible wavelength region, which also makes it an attractive candidate for solar blind photodetectors. [2][3][4] The most promising application of b-Ga 2 O 3 lies in the field of high power electronic devices such as Schottky barrier diodes (SBDs) [5][6][7] and field effect transistors (FETs). [8][9][10] It is promising to outperform the existing SiC and GaN based electronic device technologies.…”

Magnetron Sputter-Deposited β-Ga2O3 Films on c-Sapphire Substrate: Effect of Rapid Thermal Annealing Temperature on Crystalline Quality

“…In Figure 4c,f, each O 1s peak in the annealed films at 800 and 900 • C comprised two peaks, O(I) at 531.62 and 530.81 eV, corresponding to the lattice oxygen Ga-O bonds of Ga 2 O 3 and O(II) at 533.11 and 532.24 eV, respectively, associated with defected oxygen sub-lattice such as oxygen-related vacancies in the Ga 2 O 3 films [55]. However, the area ratio of the O(II) to O 1s peaks in the annealed films increased from 11.73% at 800 • C to 17.69% at 900 • C, indicating that the annealed film at 900 • C had a slight increase in the oxygen vacancies.…”

Low Temperature Producing Copper‐Doped Gallium Oxide as Hole Transport Layers of Perovskite Solar Cells Enhanced by Impurity Levels

“…After separating overlapping peaks of PL spectra, five similar emission peaks can be distinguished for both samples in the UV-blue wavelength region, and two additional emission peaks appear for Ga 2 O 3 :Cu samples in the green wavelength region. The emission peaks in the UV-blue wavelength region could be related to the radiative recombination from excitons and intrinsic defects, [41,42] while two additional emission peaks at %510 and %530 nm for Ga 2 O 3 :Cu samples should be assigned to the impurity levels of Cu dopants in the bandgap of Ga 2 O 3 . And the transition energy from conduction band minimum to these impurity levels are 2.43 and 2.34 eV, respectively.…”