Efficient Assembly of Bridged β‐Ga₂O₃ Nanowires for Solar‐Blind Photodetection

Abstract

An increasing number of applications using ultraviolet radiation have renewed interest in ultraviolet photodetector research. Particularly, solar‐blind photodetectors sensitive to only deep UV (<280 nm), have attracted growing attention because of their wide applicability. Among recent advances in UV detection, nanowire (NW)‐based photodetectors seem promising, however, none of the reported devices possesses the required attributes for practical solar‐blind photodetection, namely, an efficient fabrication process, a high solar light rejection ratio, a low photocurrent noise, and a fast response. Herein, the assembly of β‐Ga2O3 NWs into high‐performance solar‐blind photodetectors by use of an efficient bridging method is reported. The device is made in a single‐step chemical vapor deposition process and has a high 250‐to‐280‐nm rejection ratio (∼2 × 103), low photocurrent fluctuation (<3%), and a fast decay time (<<20 ms). Further, variations in the synthesis parameters of the NWs induce drastic changes in the photoresponse properties, which suggest a possibility for tuning the performance of the photodetectors. The efficient fabrication method and high performance of the bridged β‐Ga2O3 NW photodetectors make them highly suitable for solar‐blind photodetection.

Recent advances in large-scale assembly of semiconducting inorganic nanowires and nanofibers for electronics, sensors and photovoltaics

“…In recent years, this technique has been used to fabricate bridging nanowire devices such as gas sensors, photodetectors, and transistors with Si, GaN, and ZnO. [96][97][98][99][100][101][102][103][104][105][106][107] The bridging method which was first demonstrated by Haraguchi et al 96 by growing GaAs nanowires means that the wires can be laterally grown across a trench between two electrode posts which were already etched on a substrate. The schematic diagrams are shown in Fig.…”

“…These nanowire devices can be used as gas sensors, photodetectors, and transistors. [104][105][106] Particularly, Kim et al 107 demonstrated that this method could be used to directly grow Si nanowire-based AND and OR diode logic gates with excellent rectifying behaviors, and photovoltaic elements in parallel in series, with tunable power output.…”

Light-emitting Ga-oxide nanocrystals in glass: a new paradigm for low-cost and robust UV-to-visible solar-blind converters and UV emitters

“…For this reason, important results have recently been obtained in the eld of optoelectronic solar-blind 'active' transducers by means of Ga-oxide nanowire assemblies. 8 Instead, the production of crystalline Ga-oxide as optical quality macroscopic components for 'passive' UV-to-visible windows is too expensive to be competitive with devices employing UV-sensitive or intensied detectors, even though quite complex and expensive. At present, the lack of low-cost alternative solutions for simultaneous UV and visible imaging prevents us from monitoring on a large-scale a wide variety of UV-emitting invisible events, which can affect human safety conditions in working places, energy-saving, and electric power distribution reliability, such as hydrogen ames, electric sparks, and corona dispersions in high-voltage lines.…”

“…Importantly, we also show how the population of intrinsic acceptor and donor sites can be controlled by selective doping. In this way, UV and blue emissions can be optimized for different purposes, including solar-blind UV-to-blue converters 8,9 and UV-emitting devices. 27 …”

Correlation between surface modification and photoluminescence properties of β-Ga2O3 nanostructures

“…The effect of these parameters on the properties of the device can be studied by optical or electrical methods as the correlation between luminescence and electrical properties in β-Ga 2 O 3 has already been reported. 7,[22][23][24] From our previous studies, it is clear that in β-Ga 2 O 3 nanostructures, UV band intensity is more prone to be affected by surface state trapping centers as compared to blue luminescence. 7,8 This is because, the photo excited electrons which give the UV luminescence, are mobile in the conduction band and get trapped at the surface states.…”