Photodetector Arrays Based on MBE‐Grown GaSe/Graphene Heterostructure. Issue 18 (19th June 2022)

• Record Type: Journal Article
• Authors: Saroj, Rajendra K.; Guha, Puspendu; Lee, Sangmin; Yoo, Dongha; Lee, Eunsu; Lee, Jamin; Kim, Miyoung; Yi, Gyu‐Chul
• Is Part Of: Advanced optical materials. Volume 10:Issue 18(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-06-19
• Subjects: 2D heterostructures -- GaSe -- graphene -- molecular beam epitaxy -- photodetector arrays; Optical materials -- Periodicals; Photonics -- Periodicals; 620.11295
• DOI: 10.1002/adom.202200332
• Languages: English
• ISSNs: 2195-1071

Abstract

Abstract: A selective area growth of hexagonal GaSe on prepatterned graphene substrate and fabrication of a photodetector array is reported. The GaSe film is grown on the graphene substrates using a molecular beam epitaxy system and characterized for structural and morphological properties using X‐ray diffraction, Raman, and atomic force microscopy techniques. Preliminary observations indicate the growth of hexagonal GaSe layers along (001) direction on graphene film under certain optimum growth conditions. Subsequently, GaSe‐based Schottky diode photodetectors are fabricated in a single‐element and 16 × 16 crossbar array geometries. Current–voltage characteristics of the diodes show a rectifying behavior with a turn‐on voltage and a low leakage current of ≈2 V and ≈20 nA, respectively. Photoresponse characteristics of the diode are investigated by measuring wavelength‐dependent spectral response and temporal photocurrent response under illumination of different lights, including 532 nm laser and white light, with varied incident intensities. The spectral responsivity of the detector is found to be as high as 98 A W –1 at a wavelength of 500 nm with a turning‐on profile corresponding to the band edge of GaSe. The photo mapping capability of the detector array is also demonstrated in this report. Abstract : Wurtzite hexagonal GaSe (001) is directly grown on prepatterned graphene circuits using a molecular beam epitaxy system. Crossbar arrays (16 × 16) of GaSe/graphene heterostructure based Schottky photodiodes are fabricated. The photodiode pixels exhibit a high and fast response under an exposure of white and blue lights. This report also demonstrates photo‐mapping capability of the diode array device for image sensing applications.