Quasi‐Single‐Crystalline ZnGa2O4 Films via Solid Phase Epitaxy for Enhancing Deep‐Ultraviolet Photoresponse. Issue 18 (26th August 2019)

• Record Type: Journal Article
• Authors: Chen, Po‐Wei; Huang, Shiau‐Yuan; Yuan, Shuo‐Huang; Chen, Yi‐An; Hsiao, Po‐Wen; Wuu, Dong‐Sing
• Is Part Of: Advanced materials interfaces. Volume 6:Issue 18(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-08-26
• Subjects: complex oxides -- deep‐ultraviolet photodetectors -- rapid thermal annealing -- solid‐phase epitaxy -- ZnGa2O4; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.201901075
• Languages: English
• ISSNs: 2196-7350

Abstract

Abstract: The complex‐oxide materials are multifunctional materials, which have wide applications to the semiconductor and microelectronic fields. The ZnGa2 O4 having a wide bandgap of 5.1 eV is one of the promising materials for deep‐ultraviolet photodetector (PD) applications. The ZnGa2 O4 films are deposited by using conventional radio‐frequency magnetron sputtering which is extensively employed in the industry. However, the as‐deposited ZnGa2 O4 films show the disordered nanocrystalline structure, resulting in the relatively poor performance. Since the Zn atoms can diffuse out of the film structure during the annealing, the ZnGa2 O4 material is difficult to get the single‐crystalline structure by using the sputtering method. Here, the solid‐phase epitaxy method is used for crystallizing the ZnGa2 O4 structure via rapid thermal annealing process. The disordered crystal grains as incubated seeds are obtained in the as‐deposited ZnGa2 O4 film at the substrate temperature of 400 °C. Further annealing under the temperature of 700 °C in 1 min, the ZnGa2 O4 film structure approaches the quasi‐single‐crystalline ZnGa2 O4 structure, which is evidenced by checking the transmission electron microscopy. The responsivity of annealed ZnGa2 O4 PDs can reach 2.53 A W −1 (at 240 nm and 5 V), which shows a relative enhancement of 256% compared with the as‐deposited ZnGa2 O4 PDs. Abstract : The complex‐oxide ZnGa2 O4 films are deposited by radio‐frequency magnetron sputtering for deep‐ultraviolet photodetector applications. The as‐deposited ZnGa2 O4 films with disordered nanocrystalline structure are improved by solid‐phase epitaxy via rapid‐thermal annealing, resulting in achieving the quasi‐single‐crystalline structure. The improved responsivity of ZnGa2 O4 photodetector can reach 2.53 A W −1 (at 240 nm and 5 V), which shows a relative enhancement of 256%.