High-Gain 200 ns Photodetectors from Self-Aligned CdS-CdSe Core-Shell Nanowalls

Jinyou Xu, Katya Rechav, Ronit Popovitz-Biro, Iftach Nevo, Yishay Feldman, Ernesto Joselevich

Research output: Contribution to journalArticlepeer-review

Abstract

1D core-shell heterojunction nanostructures have great potential for high-performance, compact optoelectronic devices owing to their high interface area to volume ratio, yet their bottom-up assembly toward scalable fabrication remains a challenge. Here the site-controlled growth of aligned CdS-CdSe core-shell nanowalls is reported by a combination of surface-guided vaporliquid-solid horizontal growth and selective-area vapor-solid epitaxial growth, and their integration into photodetectors at wafer-scale without postgrowth transfer, alignment, or selective shell-etching steps. The photocurrent response of these nanowalls is reduced to 200 ns with a gain of up to 3.8 x 10(3) and a photoresponsivity of 1.2 x 10(3) A W-1, the fastest response at such a high gain ever reported for photodetectors based on compound semiconductor nanostructures. The simultaneous achievement of sub-microsecond response and high-gain photocurrent is attributed to the virtues of both the epitaxial CdS-CdSe heterojunction and the enhanced charge-separation efficiency of the core-shell nanowall geometry. Surface-guided nanostructures are promising templates for wafer-scale fabrication of self-aligned core-shell nanostructures toward scalable fabrication of high-performance compact photodetectors from the bottom-up.
Original languageEnglish
Article number1800413
Number of pages9
JournalAdvanced Materials
Volume30
Issue number20
DOIs
StatePublished - 17 May 2018

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