Density-controlled and seedless growth of laterally bridged ZnO nanorod for UV photodetector applications
| Autor: | Chien Sheng Huang, Yan-Kuin Su, Hsin-Chieh Yu, Yu Chun Huang, Jeng Je Tsai, Ming Yueh Chuang, Chih Hung Hsiao, Tsung Hsien Kao, San Lein Wu |
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| Rok vydání: | 2014 |
| Předmět: |
Materials science
business.industry Scanning electron microscope Photoconductivity Metals and Alloys Photodetector Condensed Matter Physics medicine.disease_cause Surfaces Coatings and Films Electronic Optical and Magnetic Materials Responsivity Optics Electrode Materials Chemistry medicine Optoelectronics Nanorod Electrical and Electronic Engineering business Instrumentation Noise-equivalent power Ultraviolet |
| Zdroj: | Sensors and Actuators B: Chemical. 202:810-819 |
| ISSN: | 0925-4005 |
| DOI: | 10.1016/j.snb.2014.06.004 |
| Popis: | This study develops a density-controlled and seedless growth method for laterally bridged ZnO nanorods from Au electrode for use in metal–semiconductor–metal photodetector fabrication. The effect of pre-annealing process on suppressing vertical ZnO nanorods is systematically investigated by atomic force microscopy and scanning electron microscopy. The pre-annealing process is demonstrated to have direct influence on controlling vertical/lateral ZnO nanorod density and morphology. Interlaced and density-controlled ZnO nanorods with approximate single-crystalline structure can be directly grown from the side wall of pre-annealed Au electrode fingers without seed-layer. Through pre-annealing process, dark-current can be decreased from 4.99 × 10 −4 to 7.28 × 10 −7 A with an applied voltage of 1 V. Highly dense lateral ZnO nanorod-based photodetectors produce remarkable responsivity of 7.01 × 10 3 A/W and UV/visible rejection ratio of 281.21. Moreover, a high internal photoconductive gain (10 4 –10 5 ) exists in the fabricated photodetectors. For a given bandwidth of 10 kHz and 1 V applied bias, the noise equivalent power of photodetectors with 0, 10, and 20 min pre-annealing periods are estimated to be 3.58 × 10 −13 , 6.78 × 10 −13 , and 4.86 × 10 −13 W, and correspond to normalized detectivity of 1.85 × 10 12 , 1.17 × 10 12 , and 1.99 × 10 12 cm Hz 0.5 W −1 , respectively. This result may be attributed to internal photoconductive gain mechanism and high-density bridged ZnO nanorods. Our approach provides a simple and controllable method to fabricate high-performance ultraviolet photodetectors. |
| Databáze: | OpenAIRE |
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