Top-gate ZnO thin-film transistors with a polymer dielectric designed for ultraviolet optical gating

✍ Scribed by Kimoon Lee; Jeong-M. Choi; D.K. Hwang; Min Suk Oh; J.K. Kim; Y. Jung; K. Oh; Seongil Im

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 624 KB
• Volume: 144
• Category: Article
• ISSN: 0924-4247
• DOI: 10.1016/j.sna.2008.01.012

✦ Synopsis

We report on the fabrication of ultraviolet (UV)-sensing top-gate ZnO thin-film transistors (TFTs) with a poly-4-vinylphenol (PVP) polymer gate dielectric on glass substrate. Our top-gate ZnO-TFT showed a field-effect mobility of 0.05 cm 2 /V s, maximum saturation current of 0.11 A at a gate bias of 10 V and an on/off ratio of ∼10 3 in the dark. Under UV illumination with a wavelength of 364 nm the ZnO-TFT exhibited ∼4.7 A for a drain current (at the same gate bias of 10 V), which is ∼50 times higher than without UV. Such photo-transistor action appeared more pronounced under a depletion regime of 0 V gate bias and the photo-to-dark current ratio was more than about 10 4 . By adopting this high UV-sensitivity, our inverter device with the top-gate ZnO-TFT and a load resistance well demonstrated its optical gating behavior.