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Title: Schottky-contacted vertically self-aligned ZnO nanorods for hydrogen gas nanosensor applications

Vertically well aligned ZnO nanorods (NRs) were grown on Si(100) substrate using RF magnetron sputtering technique. Scanning electron microscopy images confirms uniform distribution of NRs on 2 in. wafer with average diameter, height and density being ∼75 nm, ∼850 nm, and ∼1.5 × 10{sup 10} cm{sup −2}, respectively. X-ray diffraction reveals that the ZnO NRs are grown along c-axis direction with wurtzite crystal structure. Cathodoluminescence spectroscopy, which shows a single strong peak around 3.24 eV with full width half maxima 130 meV, indicates the high crystalline and optical quality of ZnO and very low defect density. Vertically aligned nanosensors were fabricated by depositing gold circular Schottky contacts on ZnO NRs. Resistance responses of nanosensors were observed in the range from 50 to 150 °C in 1% and 5% hydrogen in argon environment, which is below and above the explosive limit (4%) of hydrogen in air. The nanosensor's sensitivity increases from 11% to 67% with temperature from 50 to 150 °C and also shows fast response time (9–16 s) and moderate recovery time (100–200 s). A sensing mechanism is proposed based on Schottky barrier changes at heterojunctions and change in depletion region of NRs.
Authors:
; ;  [1] ;  [2] ;  [3]
  1. Department of Electrical Engineering, Indian Institute of Technology Jodhpur, Jodhpur 342011 (India)
  2. Sensors and Nanotechnology Group, CSIR-Central Electronics Engineering Research Institute, Pilani, Rajasthan 333031 (India)
  3. Materials Research Laboratory, University of Nova Gorica, Vipavska 11c, SI-5270 Ajdovšcina (Slovenia)
Publication Date:
OSTI Identifier:
22489529
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 3; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CATHODOLUMINESCENCE; CRYSTAL STRUCTURE; GOLD; HETEROJUNCTIONS; HYDROGEN; NANOSTRUCTURES; SCANNING ELECTRON MICROSCOPY; SPECTROSCOPY; SPUTTERING; SUBSTRATES; X-RAY DIFFRACTION; ZINC OXIDES