Self-Powered Solar-Blind UV Detectors Based on O-Terminated Vertical Diamond Schottky Diode with Low Dark Current, High Detectivity, and High Signal-to-Noise Ratio

Abstract

Self-powered solar-blind UV detectors were fabricated using high-quality Ru/diamond Schottky diodes. Photocurrents of 1 nA and 1.3 nA were obtained for detector Semi and Mesh under the condition of zero bias and 220 nm UV light irradiation, while the dark currents of these two detectors were 0.53 pA and 0.007 pA at 0 V, respectively. Photosensitive areas of detector Semi and Mesh were 1 mm 2 and 0.74 mm 2 , respectively. Rectification ratios as high as 1.5 × 10 7 and 5.7 × 10 8 at ±5 V for Semi and Mesh were obtained, showing good rectifying characteristics for the vertical Schottky diodes. Responsivities at 0 V of Semi and Mesh were 10.3 mA/W and 16.2 mA/W, respectively. High detectivities of 3.8 × 10 12 Jones and 5.2 × 10 13 Jones for detector Semi and Mesh indicate excellent self-powered detection performance. To make a comprehensive comparison of the performance of diamond solar-blind UV detectors, a log(I ph ) versus log(I dark ) graph was proposed, and the detector in this work showed an ultrahigh SNR of 2 × 10 5 . A high linear dynamic range of 105.9 dB was achieved for the self-powered detector Mesh.

Recent Progress in Solar-Blind Photodetectors Based on Ultrawide Bandgap Semiconductors

“…Many materials, such as Ag, Al, Au, Ru, WC etc., have been utilized to construct Schottky photodiodes . In 1996, Whitfield et al reported planar diamond photodiodes with gold Schottky and Ti/Ag/Au ohmic contacts shows a sharp cutoff in photoresponse in DUV with low dark currents under reverse biases. , To realize thermally stable Schottky contacts with diamond, Koide compared the rectifying characteristics of the metal contacts, such as Ti, Mo, Cr, Pd, Co, WC, and hafnium nitride (HfN), revealing that the Schottky electrode materials should not react with diamond at elevated temperatures. , The resulting photodetectors exhibit a high DUV/visible rejection ratio of 10 6 at a reverse bias of 2 V. In addition, the diamond-based photodiode using WC Schottky contact can operate in self-powered mode, achieving a DUV (210 nm)/visible rejection ratio of 10 5 at zero bias .…”

“…Many materials, such as Ag, Al, Au, Ru, WC etc., have been utilized to construct Schottky photodiodes. 33 In 1996, Whitfield et al reported planar diamond photodiodes with gold Schottky and Ti/Ag/Au ohmic contacts shows a sharp cutoff in photoresponse in DUV with low dark currents under reverse biases. 33a , 33b To realize thermally stable Schottky contacts with diamond, Koide compared the rectifying characteristics of the metal contacts, such as Ti, Mo, Cr, Pd, Co, WC, and hafnium nitride (HfN), revealing that the Schottky electrode materials should not react with diamond at elevated temperatures.…”

Deep Ultraviolet Photodetector: Materials and Devices

“…The peak responsivity of the photodetector was 21.8 A W −1 , and the detectivity was 1.39 × 10 12 cm Hz 1/2 W −1 when the bias voltage was 50 V (Figure 22b,c). Liu et al fabricated self-powered DUV detectors using high-quality Ru/diamond Schottky diodes [170]. Oxygen-terminated diamond was used because of its stable property and surface band bending.…”

“…(e) Dark current and (f) photocurrent (220 nm) vs. voltage for planar and groove-shaped electrode structures [160].The diamond-based Schottky photodiode is one of the most studied device geometries for solar-blind DUV photodetection. The effects of the photocurrent gain mechanism of Schottky devices and the trap state color center on the response have been studied[163][164][165][166][167][168][169][170].…”

High‐Performance UV Photodetector via Energy Band Engineering and LSPR‐Enhanced Pyro‐Phototronic Effect in Au Decorated 2D‐PbI2/1D‐ZnO Heterojunction

“…Ultraviolet (UV) photodetectors, which can convert light into electrical signals, play a crucial role in aerospace detection, missile tracking, optical communications, and fire warning. [1][2][3] The third-generated wide bandgap semiconductors represented by ZnO, [4][5][6] GaN, [7,8] SiC, [9,10] Ga 2 O 3 , [11,12] and diamond, [13] which are promising choices for constructing the heterojunction UV photodetector owing to their suitable cut-off wavelength determined by their bandgap, high chemical stability, good thermal conductivity and high saturation electron drift speed. [14][15][16] Whereas the intrinsic limits of imperfect interfacial transportation impede the further improvement of highperformance photodetector.…”