Oxygen desorption kinetics of ZnO nanorod–gated AlGaN/GaN HEMT-based UV photodetectors

In this study, we investigated the effect of gate length and surface area of the ZnO ultraviolet (UV) absorbing structure on the transient characteristics of AlGaN/GaN HEMT based UV photodetectors. The gate-areas (2, 6 and 18 μm lengths with same width of 100 μm) of AlGaN/GaN HEMTs are covered with...

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Bibliographic Details
Published in:AIP advances 2018-07, Vol.8 (7), p.075225-075225-14
Main Authors: Khan, Fasihullah, Khan, Waqar, Kim, Ji Hyun, Huda, Noor ul, Salman Ajmal, Hafiz Muhammad, Kim, Sam-Dong
Format: Article
Language:English
Subjects:
Aluminum gallium nitrides
Desorption
High electron mobility transistors
Mathematical models
Nanorods
Parameters
Photometers
Recovery time
Response time
Semiconductor devices
Surface area
Zinc oxide
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Summary:In this study, we investigated the effect of gate length and surface area of the ZnO ultraviolet (UV) absorbing structure on the transient characteristics of AlGaN/GaN HEMT based UV photodetectors. The gate-areas (2, 6 and 18 μm lengths with same width of 100 μm) of AlGaN/GaN HEMTs are covered with ZnO thin film and nanorods (NR) separately. The fabricated devices show enhancement in response speed with the reduction of gate length or the increase of ZnO surface area. The best response speed of ∼10 ms response time and ∼190 ms recovery time is measured from the NR-gated device with a gate length of 2 μm. A model for the oxygen desorption kinetics is proposed for the first time which theoretically shows that the response speed is dependent on two key parameters; light absorbing surface area and gate length. From our model analysis, it is shown that predicted response time is a strong function of these two device parameters, and the calculations show a good agreement with the experimental measurements.
ISSN:2158-3226
2158-3226
DOI:10.1063/1.5040295