Solar blind Schottky photodiode based on an MOCVD-grown homoepitaxial β-Ga2O3 thin film

Abstract

We report on a high performance Pt/n−Ga2O3/n+Ga2O3 solar blind Schottky photodiode that has been grown by metalorganic chemical vapor deposition. The active area of the photodiode was fabricated using ∼30 Å thick semi-transparent Pt that has up to 90% transparency to UV radiation with wavelengths < 260 nm. The fabricated photodiode exhibited Schottky characteristics with a turn-on voltage of ∼1 V and a rectification ratio of ∼108 at ±2 V and showed deep UV solar blind detection at 0 V. The Schottky photodiode exhibited good device characteristics such as an ideality factor of 1.23 and a breakdown voltage of ∼110 V. The spectral response showed a maximum absolute responsivity of 0.16 A/W at 222 nm at zero bias corresponding to an external quantum efficiency of ∼87.5%. The cutoff wavelength and the out of band rejection ratio of the devices were ∼260 nm and ∼104, respectively, showing a true solar blind operation with an excellent selectivity. The time response is in the millisecond range and has no long-time decay component which is common in photoconductive wide bandgap devices.

Progress in semiconductor diamond photodetectors and MEMS sensors

“…The weakness of the MSM structure is the exposed optical receiving area to air, which may suffer from pollutants and surface effect. Junction devices like the Schottky photodiode (SPD) and pn-or pin-junction photodiodes [63][64][65] can avoid the surface effect and be operated at zero bias like a solar cell. For the SPD, the Schottky contact is usually semi-transparent, partially absorbing the incident light.…”

Electrical Characterizations of Planar Ga2O3 Schottky Barrier Diodes

“…In electronic devices, the electrical parameters, such as carrier concentration, are key issues that affect the device design, construction, and operation. For doped Ga 2 O 3 and/or the flakes exfoliated from the bulk single crystal, the electron concentrations are reported as 10 16 –10 20 cm −3 [ 11 , 12 , 13 , 14 ], while in fact, the un-doped Ga 2 O 3 has a high resistance due to the large E g , thus it is very hard to obtain some electrical parameters via the conventional Hall measurement. Additionally, a systematic and comprehensive study for electrical characterizations such as on-state resistance ( R on ), Schottky barrier height ( ), the ideal factor ( n ), series resistance ( R s ) and the carrier concentration ( N d ) of Ga 2 O 3 Schottky devices is less reported.…”

Dual‐Channel Solar‐Blind UV Photodetector Based on β‐Ga2O3

“…The resulting sensitivity value of the photodetector under study is close to the sensitivity of the Schottky diodes . For comparison, the sensitivity in the photovoltaic mode of measurement for β‐Ga 2 O 3 photodiodes with an Au Schottky contact fabricated on single‐crystal substrates was 10 3 A W −1 and that for a Schottky photodiode based on an MOCVD‐grown homoepitaxial β‐Ga 2 O 3 thin‐film Pt‐β‐Ga 2 O 3 was 0.16 A W −1 …”

“…Gallium oxide allows one to use direct interband transitions, thus achieving a maximum in selectivity as well as insensitivity to the visible and infrared light. Photodetectors based on gallium oxide are already created in the form of Schottky diodes and more complex structures …”