TY - JOUR
T1 - Improvements of transparent electrode materials for GaN metal-semiconductor-metal photodetectors
AU - Wuu, Dong Sing
AU - Hsu, Shun Chen
AU - Horng, Ray-Hua
PY - 2004/12/1
Y1 - 2004/12/1
N2 - Metal-semiconductor-metal (MSM) photodetectors based on GaN grown on (0 0 0 1) sapphire were fabricated and characterized. The responsivity of the Pt/GaN MSM device is low due to the blocking of incoming light by Pt electrodes. Although this problem can be partly solved by the transparent indium-tin oxide (ITO) contact, the range of operation voltage for ITO/GaN MSM devices is limited by the internal gain. Transparent multilayered electrode is proposed in this work by incorporating various intermediate layers (Ti, TiO2, and Ti/TiO2). The dark current of the ITO/TiO2/GaN contact is two orders of magnitude lowerthan that of the ITO/Ti/GaN contact. The thin TiO2 barrier also contributes the lower responsivity of the ITO/TiO2/GaN structure. By introducing a thin Ti/TiO2 interlayer at the ITO-GaN interface, a significant decrease in the dark current and an increase in responsivity can be achieved simultaneously. The photo-to-clark current contrast can reach 6 × 105, and the responsivity shows no discernible internal gain under a bias between 2.5 and 7.5V.
AB - Metal-semiconductor-metal (MSM) photodetectors based on GaN grown on (0 0 0 1) sapphire were fabricated and characterized. The responsivity of the Pt/GaN MSM device is low due to the blocking of incoming light by Pt electrodes. Although this problem can be partly solved by the transparent indium-tin oxide (ITO) contact, the range of operation voltage for ITO/GaN MSM devices is limited by the internal gain. Transparent multilayered electrode is proposed in this work by incorporating various intermediate layers (Ti, TiO2, and Ti/TiO2). The dark current of the ITO/TiO2/GaN contact is two orders of magnitude lowerthan that of the ITO/Ti/GaN contact. The thin TiO2 barrier also contributes the lower responsivity of the ITO/TiO2/GaN structure. By introducing a thin Ti/TiO2 interlayer at the ITO-GaN interface, a significant decrease in the dark current and an increase in responsivity can be achieved simultaneously. The photo-to-clark current contrast can reach 6 × 105, and the responsivity shows no discernible internal gain under a bias between 2.5 and 7.5V.
UR - http://www.scopus.com/inward/record.url?scp=6044267530&partnerID=8YFLogxK
U2 - 10.1023/B:JMSE.0000045301.37195.d7
DO - 10.1023/B:JMSE.0000045301.37195.d7
M3 - Article
AN - SCOPUS:6044267530
VL - 15
SP - 793
EP - 796
JO - Journal of Materials Science: Materials in Electronics
JF - Journal of Materials Science: Materials in Electronics
SN - 0957-4522
IS - 12
ER -