TY - JOUR
T1 - Influence of grain size and room-temperature sputtering condition on optical and electrical properties of undoped and Ga-doped ZnO thin films
AU - Kim, Do Hyun
AU - Jeon, Hoonha
AU - Leem, Jae Young
AU - Jeon, Minhyon
AU - Verma, Ved Prakash
AU - Choi, Wonbong
AU - Lee, Seong Hui
AU - Moon, Jooho
PY - 2007/12
Y1 - 2007/12
N2 - The optical and the electrical properties of undoped zinc-oxide (ZnO) thin films of various thicknesses were compared with those of Ga-doped (GZO) thin films. Transparent, high-quality undoped ZnO and GZO films were deposited successfully using radio-frequency (RF) sputtering at room temperature. The films were polycrystalline with a hexagonal structure and a strongly preferred orientation along the c-axis. The films had an average optical transmission >85 % in the visible part of the electromagnetic spectrum. The undoped ZnO thin films were more transparent than the GZO thin films. The ZnO thin-film transistors (TFTs) were operated in the enhancement mode with a threshold voltage of 2.5 V. In contrary, the Ga-doped ZnO TFTs were operated in a depletion mode with a threshold voltage of-3.4 V. We successfully demonstrated undoped and the Ga-doped ZnO TFTs by using conventional SiO2 gate insulators at room temperature. We postulate that undoped ZnO films, which have not been treated to improve the optical properties, can be used, instead of doped ZnO films, in transparent devices for next generation optoelectronic devices.
AB - The optical and the electrical properties of undoped zinc-oxide (ZnO) thin films of various thicknesses were compared with those of Ga-doped (GZO) thin films. Transparent, high-quality undoped ZnO and GZO films were deposited successfully using radio-frequency (RF) sputtering at room temperature. The films were polycrystalline with a hexagonal structure and a strongly preferred orientation along the c-axis. The films had an average optical transmission >85 % in the visible part of the electromagnetic spectrum. The undoped ZnO thin films were more transparent than the GZO thin films. The ZnO thin-film transistors (TFTs) were operated in the enhancement mode with a threshold voltage of 2.5 V. In contrary, the Ga-doped ZnO TFTs were operated in a depletion mode with a threshold voltage of-3.4 V. We successfully demonstrated undoped and the Ga-doped ZnO TFTs by using conventional SiO2 gate insulators at room temperature. We postulate that undoped ZnO films, which have not been treated to improve the optical properties, can be used, instead of doped ZnO films, in transparent devices for next generation optoelectronic devices.
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U2 - 10.3938/jkps.51.1987
DO - 10.3938/jkps.51.1987
M3 - Article
AN - SCOPUS:38349166098
VL - 51
SP - 1987
EP - 1992
JO - Journal of the Korean Physical Society
JF - Journal of the Korean Physical Society
SN - 0374-4884
IS - 6
ER -