Browsing by Subject "Photodetectors (PDs)"

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    Performance enhancement of GaN metal-semiconductor-metal ultraviolet photodetectors by insertion of ultrathin interfacial HfO2 layer
    (AVS Science and Technology Society, 2015) Kumar, M.; Tekcan, B.; Okyay, Ali Kemal
    The authors demonstrate improved device performance of GaN metal-semiconductor-metal ultraviolet (UV) photodetectors (PDs) by ultrathin HfO2 (UT-HfO2) layer on GaN. The UT-HfO2 interfacial layer is grown by atomic layer deposition. The dark current of the PDs with UT-HfO2 is significantly reduced by more than two orders of magnitude compared to those without HfO2 insertion. The photoresponsivity at 360 nm is as high as 1.42 A/W biased at 5 V. An excellent improvement in the performance of the devices is ascribed to allowed electron injection through UT-HfO2 on GaN interface under UV illumination, resulting in the photocurrent gain with fast response time. © 2015 American Vacuum Society.
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    ItemOpen Access
    UV/vis range photodetectors based on thin film ALD grown ZnO/Si heterojunction diodes
    (IOP Publishing, 2013) Alkis, S.; Tekcan, B.; Nayfeh, A.; Okyay, Ali Kemal
    We present ultraviolet-visible (UV/vis) range photodetectors (PDs) based on thin film ZnO (n)/Si (p) heterojunction diodes. ZnO films are grown by the atomic layer deposition (ALD) technique at growth temperatures of 80, 150, 200 and 250 ° C. The fabricated ZnO (n)/Si (p) photodetectors (ZnO-Si-PDs) show good electrical rectification characteristics with ON/OFF ratios reaching up to 103. Under UV (350 nm wavelength) and visible (475 nm wavelength) light illumination, the ZnO-Si-PDs give photoresponsivity values of 30-37 mA W-1 and 74-80 mA W-1 at 0.5 V reverse bias, respectively. Photoluminescence (PL) spectra of ALD grown ZnO thin films are used to support the results.