Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7134263 | Sensors and Actuators A: Physical | 2016 | 6 Pages |
Abstract
Metal-semiconductor-metal (MSM) structured solar blind photodetectors were fabricated based on various Mg content wurtzite MgxZn1âxO epitaxial films grown via pulsed metal organic chemical vapor deposition. The response spectra of the devices showed a peak position that shifts from â¼383 nm to 276 nm for Mg content, x, between 0.0 and 0.51, covering a wide portion of the ultra-violet spectral region, extending well into the solar blind window. At 10 V bias, a large responsivity of â¼1.8 Ã 104 A/W was obtained at 276 nm for a device based on a high Mg content (x = 0.51) MgZnO film. To the best of our knowledge, this responsivity is the highest ever reported for a MgZnO based device and its origin is attributed to large internal gain resulting from carrier trapping at the MgZnO/Ni/Au interface. This is confirmed by the presence of an asymmetric Schottky barrier height on the two MSM contacts. Conversely, the response speed of the devices was slow with the 10%-90% rise and fall times measured to be in the millisecond range. The results reported in this work show the realization of high responsivity MgZnO based solar blind photodetectors, providing a significant step in the development of MgZnO alloy based of detector.
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Authors
Fikadu Alema, Brian Hertog, Oleg Ledyaev, Dmitry Volovik, Ross Miller, Andrei Osinsky, Sara Bakhshi, Winston V. Schoenfeld,