Ultraviolet and visible photo-response of transparent conductive Al-doped ZnO (AZO)/n-Silicon isotype heterojunction device

In this work, the electrical and photoresponse measurements of a transparent conductive Al-doped ZnO (AZO)/n-Si heterojunction device were conducted in visible light and UV wavelengths. AZO film was deposited by sputtering onto an n-Si wafer and investigated by means of morphological, chemical and electrical characterizations. The AZO/n-Si rectifying device exhibits an excellent reproducibility without noticeable variations after 90 days of measurements. At self-powered mode, the maximum on/off ratios were determined as 3081 for visible light and 4778 for UV light illumination of 365 nm. The responsivity and detectivity of the AZO/n-Si photodetector were 0.128 A W-1 and 1.05 x 10(11) Jones for 365 nm, whereas they were 0.055 A W-1 and 4.60 x 10(10) Jones for 395 nm, respectively (at -2.0 V). This study demonstrated that the n-AZO/n-Si isotype heterojunction photodetector was fabricated at low cost and it is a potential candidate in both the visible region and the UV region with a good performance, in contrast to the widely studied pn heterojunctions.