Deep-Level Traps Responsible for Persistent Photocurrent in Pulsed-Laser-Deposited β-Ga2O3 Thin Films

Abstract

Gallium oxide (β-Ga2O3) is emerging as a promising wide-bandgap semiconductor for optoelectronic and high-power electronic devices. In this study, deep-level defects were investigated in pulsed-laser-deposited epitaxial films of β-Ga2O3. A deep ultraviolet photodetector (DUV) fabricated on β-Ga2O3 film showed a slow decay time of 1.58 s after switching off 250 nm wavelength illumination. Generally, β-Ga2O3 possesses various intentional and unintentional trap levels. Herein, these traps were investigated using the fractional emptying thermally stimulated current (TSC) method in the temperature range of 85 to 473 K. Broad peaks in the net TSC curve were observed and further resolved to identify the characteristic peak temperature of individual traps using the fractional emptying method. Several deep-level traps having activation energies in the range of 0.16 to 1.03 eV were identified. Among them, the trap with activation energy of 1.03 eV was found to be the most dominant trap level and it was possibly responsible for the persistent photocurrent in PLD-grown β-Ga2O3 thin films. The findings of this current work could pave the way for fabrication of high-performance DUV photodetectors.

Direct Observation of the Stretching of the Photoinduced Current Relaxation in α-Ga2O3 Schottky Diodes

“…7,9,18 The nature of the deep hole traps in question is under intense discussion. In 19 Tak et al demonstrated using temperature scanning and thermally stimulated current characterization that such traps activation energy was 0.64 eV and 1.03 eV. These values are in good agreement with our results 20 obtained in Si-doped β-Ga 2 O 3 films after high-energy proton irradiation (20 MeV, fluence 10 14 cm −2 ).…”

Self-powered photo diodes based on Ga-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=-/n-GaAs structures

“…Traps are localized in the band gap of the oxide film [12][13][14] and at the Ga 2 O 3 /GaAs interface. Owing to a significant mismatch between the parameters of a monoclinic Ga 2 O 3 lattice and a sphalerite GaAs lattice, a high density of surface states at the interface is expected.…”

A Comprehensive Review on Recent Developments in Ohmic and Schottky Contacts on Ga2O3 for Device Applications

“…The same surface treatment using HCl and H 2 O 2 was used to form SCs using four different metals (Mo, Ni, W, and Au) on (100)-oriented β-Ga 2 O 3 bulk substrates grown by the Czochralski method (CZ) . In contrast to the results observed for (2̅01) β-Ga 2 O 3 SBDs, SBHs for these metals increased with the increase in metal work function value. Anomalous behavior was observed for Au SCs similar to Au SCs on (010) β-Ga 2 O 3 substrate .…”

“…β-Ga 2 O 3 has a high breakdown electric field strength of 8 MV/cm and exceptional Baliga figure of merit (BFOM) and Johnson’s figure of merit (JFOM) due to ultrawide bandgap of 4.6–4.9 eV, much higher than those of SiC and GaN. β-Ga 2 O 3 has a high saturation electron velocity ( v s ) of 2 × 10 7 cm/s, which allows for high current density and high-frequency operation. ,− …”