Thermally phase-transformed In2Se3 nanowires for highly sensitive photodetectors.
The photoresponse characteristics of In2Se3 nanowire photodetectors with the κ-phase and α-phase structures are investigated. The as-grown κ-phase In2Se3 nanowires by the vapor-liquid-solid technique are phase-transformed to the α-phase nanowires by thermal annealing. The photoresponse performances of the κ-phase and α-phase In2Se3 nanowire photodetectors are characterized over a wide range of wavelengths (300-900 nm). The phase of the nanowires is analyzed using a high-resolution transmission microscopy equipped with energy dispersive X-ray spectroscopy and X-ray diffraction. The electrical conductivity and photoresponse characteristics are significantly enhanced in the α-phase due to smaller bandgap structure compared to the κ-phase nanowires. The spectral responsivities of the α-phase devices are 200 times larger than those of the κ-phase devices. The superior performance of the thermally phase-transformed In2Se3 nanowire devices offers an avenue to develop highly sensitive photodetector applications.
Department of Electrical Engineering, Pohang University of Science and Technology, Pohang, Gyeongbuk, 790-784, Republic of Korea.
Daegun
D
Kang
Taiuk
T
Rim
Chang-Ki
CK
Baek
M
M
Meyyappan
Jeong-Soo
JS
Lee
In2Se3; indium selenide; photodetectors; α-phase; κ-phase