COMMUNICATION
www.advmat.de
High-Performance Blue/Ultraviolet-Light-Sensitive ZnSe-Nanobelt Photodetectors By Xiaosheng Fang,* Shenglin Xiong,* Tianyou Zhai,* Yoshio Bando, Meiyong Liao, Ujjal K. Gautam, Yasuo Koide, Xiaogang Zhang, Yitai Qian, and Dmitri Golberg
One-dimensional (1D) nanostructures have been studied extensively with respect to fundamental properties and potential applications in nanoscale devices, due to their high surfaceto-volume ratios (SVRs) and rationally designed surfaces.[1–4] Nanoscale devices fabricated using individual 1D nanostructures were demonstrated as ultrasensitive nanosensors for detecting a wide range of gases, chemicals, and biomedical species in both commercial applications and laboratory tests.[5–7] Nanowires and nanobelts represent an important and broad class of 1D nanostructures, standing at the forefront of nanoscience and nanotechnology.[1] A nanobelt, first reported by Wang and co-workers in 2001, is a 1D structurally controlled nanomaterial that has a well-defined chemical composition, crystallography, and enclosing surfaces.[8] With a large surface area exposed to the light, various nanobelts/nanoribbons have been assembled into nanometer-scale multiband light sensors.[9–12] Zinc selenide (ZnSe), an important II–VI compound semiconductor with a wide direct bandgap of 2.70 eV (460 nm) at room temperature (RT), has long been considered as a prospective material for optoelectronic devices.[13–15] ZnSe is used in II–VI light-emitting diodes (LEDs) and diode lasers working in the blue-light region. As compared to Si and GaAs, ZnSe is more sensitive to blue/UV light. Despite the abundant research on the growth and optical properties of 1D ZnSe
[*] Dr. X. S. Fang, Dr. T. Y. Zhai, Prof. Y. Bando, Dr. U. K. Gautam, Prof. D. Golberg International Center for Young Scientists (ICYS) and International Center for Materials Nanoarchitectonics (MANA) National Institute for Materials Science (NIMS) Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan) E-mail: [email protected] or [email protected]; [email protected] Dr. S. L. Xiong, Prof. X. G. Zhang College of Material Science & Engineering Nanjing University of Aeronautics and Astronautics Nanjing, 210016 (PR China) E-mail: [email protected] Dr. M. Y. Liao, Dr. Y. Koide Sensor Materials Center, NIMS Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan) Prof. Y. T. Qian Hefei National Laboratory for Physical Sciences at Microscale University of Science and Technology of China Hefei, Anhui, 230026 (PR China)
DOI: 10.1002/adma.200902126
5016
nanostructures of different morphologies it is noted that, to date, there has been only limited research devoted to their photoelectric properties.[16–19] The reported 1D ZnSe nanostructures suffered from either high dark currents or poor stabilities. It is still a challenge to develop an effective photodetector with highperformance characteristics, including stable and reproducible photocurrent, high photocurrent/dark-current ratio, and fast time response. In this Communication, we present a facile and original strategy for the preparation of ultralong ZnSe nanobelts via the en-assisted ternary solution technique based on the modified procedure of Reference [20]. First, precursor ZnSe 3en nanobelts have been successfully fabricated. Single-crystalline-ZnSe nanobelts were then synthesized by annealing of such precursors in pure argon atmosphere at 500 8C for 2 h. To the best of our knowledge, this is the first report on the preparation of ultralong ZnSe nanobelts via a simple solution-based route. This kind of ultralong, easily tuned/manipulated ZnSe nanobelts is valuable for nanoscale devices. Individual ZnSe-nanobelt photodetectors were then fabricated and characterized. These showed a high potential as blue/UV-light-sensitive photodetectors and ultrafast optoelectronic switches. In particular, the devices revealed an ultralow dark current (below the detection limit, 1014 A, of the current meter), a high photocurrent immediate decay ratio (>99%), and a fast time response (
www.advmat.de
High-Performance Blue/Ultraviolet-Light-Sensitive ZnSe-Nanobelt Photodetectors By Xiaosheng Fang,* Shenglin Xiong,* Tianyou Zhai,* Yoshio Bando, Meiyong Liao, Ujjal K. Gautam, Yasuo Koide, Xiaogang Zhang, Yitai Qian, and Dmitri Golberg
One-dimensional (1D) nanostructures have been studied extensively with respect to fundamental properties and potential applications in nanoscale devices, due to their high surfaceto-volume ratios (SVRs) and rationally designed surfaces.[1–4] Nanoscale devices fabricated using individual 1D nanostructures were demonstrated as ultrasensitive nanosensors for detecting a wide range of gases, chemicals, and biomedical species in both commercial applications and laboratory tests.[5–7] Nanowires and nanobelts represent an important and broad class of 1D nanostructures, standing at the forefront of nanoscience and nanotechnology.[1] A nanobelt, first reported by Wang and co-workers in 2001, is a 1D structurally controlled nanomaterial that has a well-defined chemical composition, crystallography, and enclosing surfaces.[8] With a large surface area exposed to the light, various nanobelts/nanoribbons have been assembled into nanometer-scale multiband light sensors.[9–12] Zinc selenide (ZnSe), an important II–VI compound semiconductor with a wide direct bandgap of 2.70 eV (460 nm) at room temperature (RT), has long been considered as a prospective material for optoelectronic devices.[13–15] ZnSe is used in II–VI light-emitting diodes (LEDs) and diode lasers working in the blue-light region. As compared to Si and GaAs, ZnSe is more sensitive to blue/UV light. Despite the abundant research on the growth and optical properties of 1D ZnSe
[*] Dr. X. S. Fang, Dr. T. Y. Zhai, Prof. Y. Bando, Dr. U. K. Gautam, Prof. D. Golberg International Center for Young Scientists (ICYS) and International Center for Materials Nanoarchitectonics (MANA) National Institute for Materials Science (NIMS) Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan) E-mail: [email protected] or [email protected]; [email protected] Dr. S. L. Xiong, Prof. X. G. Zhang College of Material Science & Engineering Nanjing University of Aeronautics and Astronautics Nanjing, 210016 (PR China) E-mail: [email protected] Dr. M. Y. Liao, Dr. Y. Koide Sensor Materials Center, NIMS Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan) Prof. Y. T. Qian Hefei National Laboratory for Physical Sciences at Microscale University of Science and Technology of China Hefei, Anhui, 230026 (PR China)
DOI: 10.1002/adma.200902126
5016
nanostructures of different morphologies it is noted that, to date, there has been only limited research devoted to their photoelectric properties.[16–19] The reported 1D ZnSe nanostructures suffered from either high dark currents or poor stabilities. It is still a challenge to develop an effective photodetector with highperformance characteristics, including stable and reproducible photocurrent, high photocurrent/dark-current ratio, and fast time response. In this Communication, we present a facile and original strategy for the preparation of ultralong ZnSe nanobelts via the en-assisted ternary solution technique based on the modified procedure of Reference [20]. First, precursor ZnSe 3en nanobelts have been successfully fabricated. Single-crystalline-ZnSe nanobelts were then synthesized by annealing of such precursors in pure argon atmosphere at 500 8C for 2 h. To the best of our knowledge, this is the first report on the preparation of ultralong ZnSe nanobelts via a simple solution-based route. This kind of ultralong, easily tuned/manipulated ZnSe nanobelts is valuable for nanoscale devices. Individual ZnSe-nanobelt photodetectors were then fabricated and characterized. These showed a high potential as blue/UV-light-sensitive photodetectors and ultrafast optoelectronic switches. In particular, the devices revealed an ultralow dark current (below the detection limit, 1014 A, of the current meter), a high photocurrent immediate decay ratio (>99%), and a fast time response (
