Ultraviolet (UV) radiation has a variety of impacts including the health of humans, the production of crops, and the lifetime of buildings. Based on the photovoltaic effect, self-powered UV photodetectors can measure and monitor UV radiation without any power consumption. However, the current low photoelectric performance of these detectors has hindered their practical use. In our study, a super-high-performance self-powered UV photodetector based on a GaN/Sn:Ga 2 O 3 pn junction was generated by depositing a Sn-doped n-type Ga 2 O 3 thin film onto a p-type GaN thick film. The responsivity at 254 nm reached up to 3.05 A/W without a power supply and had a high UV/visible rejection ratio of R 254 nm /R 400 nm = 5.9 × 10 3 and an ideal detectivity at 1.69 × 10 13 cm•Hz 1/2 •W −1 , which is well beyond the level of previous self-powered UV photodetectors. Moreover, our device also has a low dark current (1.8 × 10 −11 A), a high I photo /I dark ratio (∼10 4 ), and a fast photoresponse time of 18 ms without bias. These outstanding performance results are attributed to the rapid separation of photogenerated electron−hole pairs driven by a high built-in electric field in the interface depletion region of the GaN/ Sn:Ga 2 O 3 pn junction. Our results provide an improved and easy route to constructing high-performance self-powered UV photodetectors that can potentially replace traditional high-energy-consuming UV detection systems. KEYWORDS: self-powered, ultraviolet photodetector, GaN/Sn:Ga 2 O 3 pn junction, superhigh photoresponsivity, 3.05 A/W, potential barrier U ltraviolet radiation has a significant impact on humankind. Some benefits are UV's ability to facilitate the synthesis of vitamin D, kill germs, and treat or prevent rickets when our skin is exposed to moderate UV light. 1 However, it can cause cataracts and skin cancer and accelerate the aging process due to an excessive amount of UV radiation. 1,2 Additionally, UV radiation strongly affects the production of crops and the lifetime of buildings. Fortunately, UV radiation can be measured and monitored using semiconductor UV photodetectors based on Einstein's photoelectric effect, which transforms UV radiation to measurable electronic signals. After decades of steady development, modern UV photodetectors, with high performances in photoresponsivity, signal-to-noise ratios, stability, and speed, have gained interest recently for their applications in environmental monitoring, advanced communications, air purification, leak detection, space research, etc. 3−13 Unfortunately, to acquire reasonable detectivity, an external electric field is applied to photodetectors to separate the photogenerated electron−hole pairs. 5−13 Therefore, external power sources are generally necessary. This makes photodetectors overall uneconomical and complex. On the contrary, self-powered photodetectors can help solve the energy issues and have attracted significant attention. 14−19 Compared to traditional photodetectors, self-powered structures, based on the photovoltaic effect su...

A self-powered ultraviolet photodetector with an extremely high responsivity (54.43 mA W−1) was fabricated by constructing p–n junction of GaN/Ga2O3 films.

Solar-blind photodetectors have been widely developed because of their great potential application in biological analysis, ultraviolet communication, and so on. Photodetectors constructed by vertically aligned nanorod arrays (NRAs), have attracted intensive interest recently owing to the virtues of low light reflectivity and rapid electron transport. However, limited by the insufficient contact between the upper electrode and NRAs because of uneven NRAs, photogenerated carriers cannot be effectively separated and transferred. In this work, a novel photoelectrochemical (PEC) type self-powered solar-blind photodetectors constructed in the form of Ga2O3 NRAs/electrolyte solid/liquid heterojunction with a large photogenerated carrier separation interface has been fabricated, β-Ga2O3 NRAs PEC photodetector shows a photoresponsivity of 3.81 mA/W at a bias voltage of 0 V under the 254 nm light illumination with the light intensity of 2.8 mW/cm2, thus yielding a I photo/I dark ratio of 28.97 and an external quantum efficiency of 1.86%. Our results provide a novel device structure of solar-blind photodetector with high efficient deep-ultraviolet photodetection and low power consumption.

Precise control of dopant composition is critical for the production of semiconductor films with desired properties. Here, we present results on the electrical properties for Si doped Ga2O3 films grown by pulsed laser deposition technique (PLD). The Si composition in the films can be controlled by changing the target composition as observed from the secondary ion mass spectroscopy measurement. The carrier density of the films is varied from the order of 1015 to 1020 cm−3 while the conductivity from 10−4 to 1 S cm−1 as measured by Hall equipment. The carrier density of the films has been verified by Kelvin force microscopy, which shows an increased surface work function with the increase of carrier density. The results suggest that the carrier density of β-Ga2O3 films is controllable by Si doping by PLD, paving a way to develop the Ga2O3 film-based electronic devices.

Ga2O3 thin films were deposited on (111) Si substrate by pulsed laser deposition method. X-ray photoelectron spectroscopy has been used to determine the valence band offset at Ga2O3/Si heterojunction interface. We measured the binding energies of Si 2p and Ga 2p3/2 core levels and the valence band maxima energies. The valence band offset is determined to be 3.5 ± 0.1 eV. As a consequence a type Ι heterojunction with a conduction band offset of 0.2 ± 0.1 eV is found. The determination of the band alignment of Ga2O3/Si heterojunction facilitates the design of optical and electronic devices based on the Ga2O3/Si structure.