TY - JOUR
T1 - Large-area photodetector with high-sensitivity and broadband spectral response based on composition-graded CdSSe nanowire-chip
AU - Guo, Shuai
AU - Li, Zhishuang
AU - Song, Guangli
AU - Zou, Bingsuo
AU - Wang, Xiaoxu
AU - Liu, Ruibin
N1 - Publisher Copyright:
© 2015 Elsevier B.V.All rights reserved.
PY - 2015/8/1
Y1 - 2015/8/1
N2 - The nanowire-chip based large-area and broad-band-response photodetector was realized by integrating the ternary bandgap-graded CdS1-xSex nanowire-chip on proper substrate and optimizing electrode pattern. The actual light-to-dark current ratio (Ilight/Idark) is subject to the substrate type and the electrode pattern, as well the thickness of nanowires. Up to 106 light-to-dark current ratio was obtained for the nanowire-chip photodetector with the optimized interdigital electrode parameters (0.5 mm in width, 0.5 mm in pitch), the suitable substrate - mica and appropriate nanowire thickness (70um). Although the carriers transmit from light-generated carrier centers to the electrodes through a complicated and long pathway, the photodetector of as-fabricated nanowire-chip shows much higher photocurrent and photoconductivity due to a higher photocarrier densities exist in the ternary compounds than that in binary CdS and CdSe nanowire and the intersection trap state existing between nanowires enhances the separation of electrons and holes. Uniform and broad photoresponse covering from ultraviolet to around 700 nm is attributed to the graded bandgap of different composition nanowires/nanobelts in the chip-type detector. Especially, the Ilight/Idark of nanowire-chip detector increases with the temperature decrease due to the dark noise and the scattering become lower. The chip detector with composition-graded nanowires shows good photoconductivity at room temperature and low temperature. More important, it can be fabricated by a commercial CVD route, which will satisfy the requirements in many application fields instead of Si-based detector.
AB - The nanowire-chip based large-area and broad-band-response photodetector was realized by integrating the ternary bandgap-graded CdS1-xSex nanowire-chip on proper substrate and optimizing electrode pattern. The actual light-to-dark current ratio (Ilight/Idark) is subject to the substrate type and the electrode pattern, as well the thickness of nanowires. Up to 106 light-to-dark current ratio was obtained for the nanowire-chip photodetector with the optimized interdigital electrode parameters (0.5 mm in width, 0.5 mm in pitch), the suitable substrate - mica and appropriate nanowire thickness (70um). Although the carriers transmit from light-generated carrier centers to the electrodes through a complicated and long pathway, the photodetector of as-fabricated nanowire-chip shows much higher photocurrent and photoconductivity due to a higher photocarrier densities exist in the ternary compounds than that in binary CdS and CdSe nanowire and the intersection trap state existing between nanowires enhances the separation of electrons and holes. Uniform and broad photoresponse covering from ultraviolet to around 700 nm is attributed to the graded bandgap of different composition nanowires/nanobelts in the chip-type detector. Especially, the Ilight/Idark of nanowire-chip detector increases with the temperature decrease due to the dark noise and the scattering become lower. The chip detector with composition-graded nanowires shows good photoconductivity at room temperature and low temperature. More important, it can be fabricated by a commercial CVD route, which will satisfy the requirements in many application fields instead of Si-based detector.
KW - Broad-band spectrum response
KW - CdS<inf>1-x</inf>Se<inf>x</inf> nanowire-chip
KW - Interdigital electrode
KW - Photoconductivity
UR - http://www.scopus.com/inward/record.url?scp=84938380361&partnerID=8YFLogxK
U2 - 10.1016/j.jallcom.2015.07.179
DO - 10.1016/j.jallcom.2015.07.179
M3 - Article
AN - SCOPUS:84938380361
SN - 0925-8388
VL - 649
SP - 793
EP - 800
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
ER -