Nanolayered Graphene/Hexagonal Boron Nitride/n-AlGaN Heterostructures as Solar-Blind Deep-Ultraviolet Photodetectors

Abstract

The spectral specificity of deep-ultraviolet (UV) photodetectors makes them useful in many fields, spanning from disinfection of various surfaces and water purification to optical communication. As silicon-based devices show obvious disadvantages as UV devices because of their low band gap, semiconductor materials with a wide band gap exceeding 4 eV serve as excellent alternatives. In this paper, by the integration of the unique properties of each constituent material, we design a nanolayered graphene/insulator/semiconductor (graphene/hBN/n-AlGaN) deep-UV photodetector with high performance. The wide-band gap AlGaN semiconductor enables the detection of deep-UV signals without the requirement of a UV-pass filter and thus acts as a true solar-blind photodetector. In addition, the several nanolayered graphene–hBN heterostructure is utilized to enhance the performance of photodetectors, which successfully solves the strain issue between graphene and the conventional bulk insulators. Besides, the high transparency of graphene can enable incident light to directly excite the active layer with negligible optical loss, and the two-dimensional hBN insulator is beneficial to reduce dark current and assist the quantum tunneling of photogenerated carriers. Interestingly, the photodetectors demonstrated in this work show the highest responsivity and detectivity compared with previously reported AlGaN-based deep-UV photodetectors.

High Temperature Resistant Solar‐Blind Ultraviolet Photosensor for Neuromorphic Computing and Cryptography

“…Accordingly, the D* was calculated to be 5.8 × 10 12 Jones, which is among the best values for the reported solarblind photodetectors (Figure 2g). [2,3,16,27,28,[31][32][33][34][35][36][37][38][39][40][41][42][43][44] Due to the large number of oxygen vacancy defects in the GaO X films, the device has a long relaxation time (Figure S5, Supporting Information). Then, the uniformity of the 12 × 12 pixels was verified by making statistics on dark current and photocurrent (10 V, 70 nW cm −2 ).…”

Large‐Scale, Uniform‐Patterned CsCu2I3 Films for Flexible Solar‐Blind Photodetectors Array with Ultraweak Light Sensing

“…The comparison between our solar-blind PDs array and previously reported devices based on other materials is shown in Figure 3i. [6,12,14,17,39,[45][46][47][48][49][50][51][52][53][54][55] Our device array, which operates with a low bias voltage, demonstrates a high responsivity and excellent capability for weak light sensing. Considering the large-scale array configuration, it is much more competitive than previously single devices for practical applications.…”

Recent advances and prospects for a GaN-based hybrid type ultraviolet photodetector

“…Meanwhile, deposited ZnO quantum dots on top of the grapheme facilitate efficient carrier transfer and thus enhance photocurrent. Using a similar architecture, Wu et al [190] fabricated a graphene/BN/AlGaN heterostructure solar-blind UV-PD, and achieved a DUV responsivity of 3.63 A W −1 at bias voltage of 5 V.…”