Photoconductive properties of polycrystalline selenium based lateral MISIM photodetectors of high quantum efficiency using different dielectrics as the charge blocking layer

Cheng Yi Chang, Yu Wei Huang, Yi Jie Lin, Jye Yow Liao, Jian Siang Lin, Yi Ming Li, Chieh Yang Chen, Jeng Tzong Sheu, Fu Ming Pan*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

We studied the photoconductive performance of polycrystalline selenium (pc-Se) based photodetectors with a lateral metal–insulator-semiconductor-insulator–metal (MISIM) device structure. The insulator layer is a 10 nm-thick Ga2O3, HfO2, or Al2O3 thin film, and used as a charge blocking layer (CBL) to suppress dark current injected from the Al electrodes. The dark current suppression primarily depends on the barrier height of the junctions between the CBLs and electrodes. The Ga2O3 CBL exhibits a poor dark current suppression compared to the HfO2 and the Al2O3 CBLs because of a lower electron barrier at the cathode. The lateral pc-Se photodetectors exhibit a very high internal photocurrent gain due to Fowler–Nordheim tunneling at relatively low applied voltages. The better crystallinity of pc-Se grains formed on the Ga2O3 CBL leads to a higher photoconversion efficiency for the MISIM-Ga2O3 photodetector. Compared with amorphous Se based lateral MISIM photodetectors, the pc-Se photodetectors demonstrate a uniform and much better photoconductive performance over the visible spectrum.

Original languageEnglish
Pages (from-to)12956-12965
Number of pages10
JournalJournal of Materials Science: Materials in Electronics
Volume30
Issue number14
DOIs
StatePublished - 30 Jul 2019

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