Thermally Phase‐Transformed In 2 Se 3 Nanowires for Highly Sensitive Photodetectors

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 10; no. 18; pp. 3795 - 3802
• Main Authors: Kang, Daegun, Rim, Taiuk, Baek, Chang‐Ki, Meyyappan, M., Lee, Jeong‐Soo
• Format: Journal Article
• Language: English
• Published: 01.09.2014
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.201400373

The photoresponse characteristics of In 2 Se 3 nanowire photodetectors with the κ ‐phase and α ‐phase structures are investigated. The as‐grown κ ‐phase In 2 Se 3 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 In 2 Se 3 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 In 2 Se 3 nanowire devices offers an avenue to develop highly sensitive photodetector applications.