In recent years,
Ga2O3 solar-blind photodetectors
(SBPDs) have received great attention for their potential applications
in solar-blind imaging, deep space exploration, confidential space
communication, etc. In this work, we demonstrated an ultra-high-performance
ε-Ga2O3 metal–semiconductor–metal
(MSM) SBPD. The fabricated photodetectors exhibited a record-high
responsivity and fast decay time of 230 A/W and 24 ms, respectively,
compared with MSM-structured Ga2O3 photodetectors
reported to date. Additionally, the ε-Ga2O3 MSM SBPD presents an ultrahigh detectivity of 1.2 × 1015 Jones with a low dark current of 23.5 pA under an operation
voltage of 6 V, suggesting its strong capability of detecting an ultraweak
signal. The high sensitivity and wavelength selectivity of the photodetector
were further confirmed by the record-high responsivity rejection ratio
(R
250 nm/R
400 nm) of 1.2 × 105. From the temperature-dependent electrical
characteristics in the dark, the thermionic field emission and Poole–Frenkel
emission were found to be responsible for the current transport in
the low and high electric field regimes, respectively. In addition,
the gain mechanism was revealed by the Schottky barrier lowering effect
due to the defect states at the interface of the metal contact and
Ga2O3 or in the bulk of Ga2O3 based on current transport mechanism and density functional
theory calculations. These results facilitate a better understanding
of ε-Ga2O3 photoelectronic devices and
provide possible guidance for promoting their performance in future
solar-blind detection applications.
The Pt/β-Ga2O3 Schottky barrier diode and its temperature-dependent current-voltage characteristics were investigated for power device application. The edge-defined film-fed growth (EFG) technique was utilized to grow the (100)-oriented β-Ga2O3 single crystal substrate that shows good crystal quality characterized by X-ray diffraction and high resolution transmission electron microscope. Ohmic and Schottky electrodes were fabricated by depositing Ti and Pt metals on the two surfaces, respectively. Through the current-voltage (I-V) measurement under different temperature and the thermionic emission modeling, the fabricated Pt/β-Ga2O3 Schottky diode was found to show good performances at room temperature, including rectification ratio of 1010, ideality factor (n) of 1.1, Schottky barrier height (ΦB) of 1.39 eV, threshold voltage (Vbi) of 1.07 V, ON-resistance (RON) of 12.5 mΩ·cm2, forward current density at 2 V (J@2V) of 56 A/cm2, and saturation current density (J0) of 2 × 10−16 A/cm2. The effective donor concentration Nd − Na was calculated to be about 2.3 × 1014 cm3. Good temperature dependent performance was also found in the device. The Schottky barrier height was estimated to be about 1.3 eV–1.39 eV at temperatures ranging from room temperature to 150 °C. With increasing temperature, parameters such as RON and J@2V become better, proving that the diode can work well at high temperature. The EFG grown β-Ga2O3 single crystal is a promising material to be used in the power devices.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.