Pine‐Branch‐Like SnO2/ZnO Heterostructure with Suppressed Dark Current and Enhanced On/Off Ratio for Visible‐Blind UV Imaging. (11th March 2022)

• Record Type: Journal Article
• Authors: Cao, Fa; Su, Li; Yan, Tingting; Li, Ziqing; Shtansky, Dmitry V.; Fang, Xiaosheng
• Is Part Of: Advanced Electronic Materials. Volume 8:Number 7(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-03-11
• Subjects: pine‐branch‐like -- reduced dark current -- SnO 2/ZnO heterostructure -- visible‐blind; Materials -- Electric properties -- Periodicals; Materials science -- Periodicals; Magnetic materials -- Periodicals; Electronic apparatus and appliances -- Periodicals; 537
• DOI: 10.1002/aelm.202101373
• Languages: English
• ISSNs: 2199-160X

Abstract

Abstract: In general, wide bandgap semiconductors (Eg > 3.0 eV) are sensitive to visible‐blind ultraviolet (UV) radiation. However, a large dark current makes it difficult to implement efficient visible‐blind sensing, which impedes their application in visible‐blind UV image. In this work, pine‐branch‐like photodetectors (PDs) based on SnO2 /ZnO heterostructure are successfully fabricated. Compared with the high dark current (1.5 × 10 ‐8 A) and low on/off ratio (42) of SnO2 PD, the designed SnO2 /ZnO/4 (S/Z/4) PD shows a significantly reduced dark current (1.3 × 10 ‐12 A), ultrahigh on/off ratio (16 405) under 300 nm UV illumination at 1 V bias. In addition, the UV/visible rejection ratio ( R 310 / R 400 ) of S/Z/4 PD is 1193, which is almost 48‐times of that of SnO2 PD (25). This shows great promise for application in visible‐blind image sensors. The enhancement in performance is attributed to the formation of the type‐II energy band structure, the low conductivity of ZnO layer, and the light trapping effect of pine‐branch‐like structure. Moreover, the SnO2 /ZnO/4 PD also exhibits fast response speed with a rising time of 0.48 ms and decay time of 2.07 ms, which exceeds most of the metal oxide‐based PDs. The fabrication approach of pine‐branch‐like heterojunction can be extended to other one‐dimensional materials for high‐performance optoelectronic devices. Abstract : Pine‐branch‐like SnO2 /ZnO heterostructure exhibits visible‐blind imaging ability.