Synthesis and Photoresponse of Large GaSe Atomic Layers
- Publication date
- 2013
- Publisher
Abstract
We report the direct growth of large,
atomically thin GaSe single
crystals on insulating substrates by vapor phase mass transport. A
correlation is identified between the number of layers and a Raman
shift and intensity change. We found obvious contrast of the resistance
of the material in the dark and when illuminated with visible light.
In the photoconductivity measurement we observed a low dark current.
The on–off ratio measured with a 405 nm at 0.5 mW/mm<sup>2</sup> light source is in the order of 10<sup>3</sup>; the photoresponsivity
is 17 mA/W, and the quantum efficiency is 5.2%, suggesting possibility
for photodetector and sensor applications. The photocurrent spectrum
of few-layer GaSe shows an intense blue shift of the excitation edge
and expanded band gap compared with bulk material