Photocarrier Relaxation Behavior of a Single ZnO Nanowire UV Photodetector: Effect of Surface Band Bending

• Published in: IEEE electron device letters Vol. 33; no. 3; pp. 411 - 413
• Main Authors: Ming-Wei Chen, Retamal, J. R. D., Cheng-Ying Chen, Jr-Hau He
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.03.2012; Institute of Electrical and Electronics Engineers
• Subjects: Applied sciences; Cross-disciplinary physics: materials science; rheology; Electronics; Exact sciences and technology; General equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Lighting; Logic gates; Materials science; Nanoscale materials and structures: fabrication and characterization; Nanowire (NW); Optoelectronic devices; Photoconductivity; photodetector; Photodetectors; Physics; Quantum wires; relaxation time; Scanning electron microscopy; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing; surface band bending (SBB); Switches; Transistors; Zinc oxide; ZnO; Band bending; II-VI compound; Nanowire (NW); Photodetector; Switching; Relaxation time; Surface effect; Enhancement mode; Field effect transistor; Relaxation; Ultraviolet radiation; Ultraviolet detector; Wide band; Optoelectronic device; Illumination; Zinc oxide; ZnO; Nanowires; Photoelectric current; surface band bending (SBB)
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2011.2180012

The surface effect on the photocarrier relaxation behavior using a single ZnO nanowire (NW) ultraviolet (UV) photodetector has been evaluated. The pronounced surface effect leads to the enhancement-mode field-effect-transistor behavior in dark and accounts for the slow relaxation behavior after switching off the illumination. The recovery of photocurrent is found to be strongly related to the intensity of UV light and the diameter of NWs, indicating that the photocarrier relaxation behavior is dominated by surface band bending (SBB). A model for the relaxation behavior based on the SBB of NWs is proposed to interpret the experimental results.