High performance solar-blind ultraviolet photodetector based on ITO/β-Ga₂O₃ heterostructure

Abstract

The authors report an indium tin oxide (ITO) decorated solar-blind deep ultraviolet photodetectors (PDs) based on high quality β-Ga2O3 single crystal microwires (MWs). An ultrahigh photo-to-dark current (Iphoto/Idark) ratio ~107 of the PDs has been realized. Compared with In/β-Ga2O3/In MSM PD, the device with ITO as the interlayers between In and β-Ga2O3 show excellent performances, such as the high responsivity of 1720.2 A/W and 438.8 A/W under 260 nm illumination with reverse and forward bias, respectively. In addition, the device exhibited a very low dark current as low as 2.0×10-13 A and a photocurrent up to 1.0×10-6 A at the bias of -6 V (under 1.95 mW·cm-1 @260nm). The rise and fall time of the device were 0.5 s and 0.2 s, which was significantly faster than MSM structure. Moreover, the device exhibited an ultrahigh solar-blind/visible rejection ratio (R260 nm/R400 nm) of 1.09×105, a detectivity D* of 1.23×1014 Jones and the external quantum efficiency of 4180.3%. The excellent performances of the PDs are attributed to the improved carrier separating process at the ITO/β-Ga2O3 interfaces and the reduced carrier trapping behavior induced by the β-Ga2O3 surface states. The introduction of ITO between MWs and the electrodes is of great significance for the application of β-Ga2O3 based detectors.

Ultraviolet Photodetector Based on a Beta-Gallium Oxide/Nickel Oxide/Beta-Gallium Oxide Heterojunction Structure

“…The highest photoresponsivity of 1720.2 A/W was achieved in the ITO/β-Ga2O3 structure [16]. Furthermore, in the transparent amorphous Ga2O3 structure, a high responsivity of 2.66 A/W and 5.78 A/W was obtained [15,16]. This suggests that a transparent electrode structure effectively enhances photo responsivity.…”

“…Table 1 shows the comparison of structural and photo responsivity. The highest photoresponsivity of 1720.2 A/W was achieved in the ITO/β-Ga2O3 structure [16]. Furthermore, in the transparent amorphous Ga2O3 structure, a high responsivity of 2.66 A/W and 5.78 A/W was obtained [15,16].…”

“…In order to protect against UV light, proper UV photodetectors are required. Therefore, many types of UV photodetectors have been studied [14][15][16][17][18][19][20]. There are several approaches, such as amorphous film, nano-rods, and combinations with other materials.…”

Special issue on wide-bandgap semiconductors and applications

“…To improve the performance, different device structures were designed and fabricated for Ga 2 O 3 based MSM PDs. Zhang et al [28] proposed a heterojunction solar-blind detector with an indium tin oxide (ITO) layer inserted into the electrode and β-Ga 2 O 3 microwires, which enables charge carrier separation accelerated at the interface and reduces the numbers of carriers captured by the superficial states induced by β-Ga 2 O 3 . The device has a high detectivity of 1.23 × 10 14 Jones.…”

Fully Transparent and High‐Performance ε‐Ga2O3 Photodetector Arrays for Solar‐Blind Imaging and Deep‐Ultraviolet Communication

“…[ 14 ] A new type of ultra‐wide band semiconductor material, Ga 2 O 3 with a wide bandgap of ≈4.9 eV, does not require a complex alloying process and possesses high chemical stability, and can therefore be considered a natural material for solar‐blind signals detection. To date, various types of Ga 2 O 3 ‐based PDs have been proposed, including p‐n junctions, [ 15 ] heterojunctions, [ 16,17 ] Schottky diodes, [ 18 ] avalanches, [ 19 ] metal–semiconductor–metal (MSM) [ 20,21 ] and photoelectrochemical [ 22 ] PDs. Among them, MSM‐type SBDU PDs have been widely studied as their preparation is simple and they are easily integrated with electronic devices.…”