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Title: Low dark current and high speed ZnO metal–semiconductor–metal photodetector on SiO{sub 2}/Si substrate

ZnO thin films are deposited by radio-frequency magnetron sputtering on thermally grown SiO{sub 2} on Si substrates. Pt/Au contacts are fabricated by standard photolithography and lift-off in order to form a metal-semiconductor-metal (MSM) photodetector. The dark current of the photodetector is measured as 1 pA at 100 V bias, corresponding to 100 pA/cm{sup 2} current density. Spectral photoresponse measurement showed the usual spectral behavior and 0.35 A/W responsivity at a 100 V bias. The rise and fall times for the photocurrent are measured as 22 ps and 8 ns, respectively, which are the lowest values to date. Scanning electron microscope image shows high aspect ratio and dense grains indicating high surface area. Low dark current density and high speed response are attributed to high number of recombination centers due to film morphology, deducing from photoluminescence measurements. These results show that as deposited ZnO thin film MSM photodetectors can be used for the applications needed for low light level detection and fast operation.
Authors:
 [1] ;  [2] ; ;  [1] ;  [3] ;  [1] ;  [2]
  1. Nanotechnology Research Center, Bilkent University, 06800 Bilkent, Ankara (Turkey)
  2. (Turkey)
  3. Department of Physics Engineering, Hacettepe University, 06800 Beytepe, Ankara (Turkey)
Publication Date:
OSTI Identifier:
22350940
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 16; Other Information: (c) 2014 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; CURRENT DENSITY; CURRENTS; DETECTION; ELEVATORS; MAGNETRONS; METALS; PHOTODETECTORS; PHOTOLUMINESCENCE; RADIOWAVE RADIATION; RECOMBINATION; SCANNING ELECTRON MICROSCOPY; SEMICONDUCTOR MATERIALS; SILICA; SILICON OXIDES; SPUTTERING; SUBSTRATES; SURFACE AREA; THIN FILMS; VISIBLE RADIATION; ZINC OXIDES