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

Journal Article · Mon Oct 20 00:00:00 EDT 2014 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4899297· OSTI ID:22350940

Çalışkan, Deniz ^[1]; Bütün, Bayram; Çakır, M. Cihan ^[1]; Özcan, Şadan ^[2]; Özbay, Ekmel ^[1]

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1. Nanotechnology Research Center, Bilkent University, 06800 Bilkent, Ankara (Turkey)
2. Department of Physics Engineering, Hacettepe University, 06800 Beytepe, Ankara (Turkey)

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.

• OSTI ID: 22350940
• Journal Information: Applied Physics Letters, Vol. 105, Issue 16; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

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