Substrate effects on the speed limiting factor of WSe 2 photodetectors

We investigate the time-resolved photoelectric response of WSe 2 crystals on glass and flexible polyimide substrates to determine the effect of a changed dielectric environment on the speed of the photodetectors. We show that varying the substrate material can alter the speed-limiting mechanism: whi...

Full description

Saved in:
Bibliographic Details
Published in:Physical chemistry chemical physics : PCCP 2022-10, Vol.24 (41), p.25383-25390
Main Authors: Schedel, Christine, Strauß, Fabian, Kohlschreiber, Pia, Geladari, Olympia, Meixner, Alfred J., Scheele, Marcus
Format: Article
Language:English
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We investigate the time-resolved photoelectric response of WSe 2 crystals on glass and flexible polyimide substrates to determine the effect of a changed dielectric environment on the speed of the photodetectors. We show that varying the substrate material can alter the speed-limiting mechanism: while the detectors on polyimide are RC limited, those on glass are limited by slower excitonic diffusion processes. We attribute this to a shortening of the depletion layer at the metal electrode/WSe 2 interface caused by the higher dielectric screening of glass compared to polyimide. The photodetectors on glass show a tunable bandwidth, which can be increased to 2.6 MHz with increasing the electric field.
ISSN:1463-9076
1463-9084
DOI:10.1039/D2CP03364J