Ultrahigh photoconductivity of bandgap-graded CdSxSe1-x nanowires probed by terahertz spectroscopy.
Superiorly high photoconductivity is desirable in optoelectronic materials and devices for information transmission and processing. Achieving high photoconductivity via bandgap engineering in a bandgap-graded semiconductor nanowire has been proposed as a potential strategy. In this work, we report the ultrahigh photoconductivity of bandgap-graded CdSxSe1-x nanowires and its detailed analysis by means of ultrafast optical-pump terahertz-probe (OPTP) spectroscopy. The recombination rates and carrier mobility are quantitatively obtained via investigation of the transient carrier dynamics in the nanowires. By analysis of the terahertz (THz) spectra, we obtain an insight into the bandgap gradient and band alignment to carrier transport along the nanowires. The demonstration of the ultrahigh photoconductivity makes bandgap-graded CdSxSe1-x nanowires a promising candidate as building blocks for nanoscale electronic and photonic devices.
Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis, #08-03, 138634, Singapore.
Hongwei
H
Liu
Department of Physics, 2 Science Drive 3, National University of Singapore, 117542, Singapore.
Junpeng
J
Lu
State Key Laboratory of Modern Optical Instrumentation, Department of Optical Engineering, Zhejiang University, Hangzhou, Zhejiang, 310027, China.
Zongyin
Z
Yang
Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis, #08-03, 138634, Singapore.
Jinghua
J
Teng
Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis, #08-03, 138634, Singapore.
Lin
L
Ke
Department of Electrical and Electronic Engineering, South University of Science and Technology of China, 1088 Xueyuan Road, Nanshan District, Shenzhen, Guangdong, 518055, China.
Xinhai
X
Zhang
State Key Laboratory of Modern Optical Instrumentation, Department of Optical Engineering, Zhejiang University, Hangzhou, Zhejiang, 310027, China.
Limin
L
Tong
Department of Physics, 2 Science Drive 3, National University of Singapore, 117542, Singapore.
Chorng Haur
CH
Sow