Fabrication and characterization of transparent nanocrystalline ZnO thin film transistors by a sol–gel technique

[摘要] A nanocrystalline zinc oxide (ZnO) thin film-based metal–insulator–semiconductor thin film transistor (MISTFT) was fabricated by a facile sol–gel technique onto silicon di-oxide/indium tin oxide-coated glass substrates. Themicrostructural study of the ZnO thin films indicated uniform crystalline growth with typical (002) X-ray diffraction peaks for h-ZnO with a wurtzite structure. The optical transmittance of the ZnO thin films was >80% in the visible region of theelectromagnetic spectrum. The field effect transistor (FET) aluminium top contacts were fabricated using suitable shadow masking. The transfer characteristics of a typical ZnO MIS FET revealed nonlinearity in a linear plot. From the slope and crossover, we obtained a first estimate of field effect mobility ($\mu$) and threshold voltage ($V_T$) of 0.13 cm$^2$ V$^{−1}$ s$^{−1}$ and1.03 eV, respectively. The ZnO TFT operated in enhanced mode with n-channel characteristics and the drain current on–off ratio was 105. The deposition parameter needs to be optimized to obtain TFTs with a higher modulation ratio and larger field-effect mobility.

[学科分类] 材料工程

[关键词] Zinc oxide;sol–gel;thin film transistor;optical;electrical.