nn6b06468_si_001.pdf (457.05 kB)
Multimodal Photodiode and Phototransistor Device Based on Two-Dimensional Materials
journal contribution
posted on 2016-11-02, 00:00 authored by Seon Namgung, Jonah Shaver, Sang-Hyun Oh, Steven J. KoesterWith strong light–matter
interaction in their atomically
thin layered structures, two-dimensional (2D) materials have been
widely investigated for optoelectronic applications such as photodetectors
and photovoltaic devices. Depending on the aim of optoelectronic applications,
different device structures have been employed. Lateral phototransistor
structures have been employed for high optical gain, while vertical
photodiode structures have been employed for fast response and low
power operation. Herein, we demonstrate a multimodal photodetector
platform based on 2D materials, combining both a phototransistor and
a photodiode and taking the corresponding desirable characteristics
from each structure within a single device. In this platform, a multilayered
transition-metal dichalcogenide flake is transferred on top of metal
electrodes, and a transparent gate electrode is employed. The channel
region of the flake between electrodes operates as a phototransistor
providing a high gain mode, while the electrode region in the same
flake operates as a vertical Schottky photodiode providing a fast
response mode. These modes can be dynamically selected by controlling
the drain voltage and gate voltage.