Dramatic spread of substrate materials for semiconducting layer formation by spraying ZnO nanoparticles

2019 Fiscal Year Final Research Report

• Project/Area Number: 16K06263
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Electronic materials/Electric materials
• Research Institution: Shimane University
• Principal Investigator: Yoshida Toshiyuki 島根大学, 学術研究院理工学系, 講師 (50335551)
• Co-Investigator(Kenkyū-buntansha): 藤田 恭久 島根大学, 学術研究院理工学系, 教授 (10314618)
• Project Period (FY): 2016-10-21 – 2020-03-31
• Keywords: ZnOナノ粒子 / スプレー法 / 粒子層 / 塗布型トランジスター

Outline of Final Research Achievements

ZnO nanoparticle layers were formed on quartz substrates and evaluated their characteristics as semiconducting layers. The particle layer was formed by spraying method and evaporation drying method using ZnO nanoparticle dispersion liquid. By comparing these two methods, we evaluated the surface structure, sheet resistance, mobility, etc., and showed the ZnO particles’ particle size dependence and conductivity type dependence. The carrier conduction in the obtained ZnO nanoparticle layers also showed a behavior that could not be explained by a general drift-diffusion model, and the results suggesting hopping conduction via defects on the particle surface were obtained. We also attempted thermal diffusion doping of Ga atoms into ZnO particles in order to lower the resistance of the particle layer, and dramatic reduction of the sheet-resistance (M- or G-Ohm/sq level → sub-k-Ohm/sq) could be achieved.

Free Research Field

半導体工学

Academic Significance and Societal Importance of the Research Achievements

酸化物半導体の微粒子層を，スプレー法または蒸発乾燥法により形成した。粒子層は，高性能なエピタキシャル膜と比べると性能は劣るが，低コスト化や大面積化が容易で，何より下地基板を選ばないというメリットがある。本研究ではZnOナノ粒子層をチャネルとする薄膜トランジスタ（TFT）を形成することを目的としており，粒径や伝導型などの違いや，キャリア伝動機構について評価を進めている。またTFT性能向上において，現状最も影響を与えている低抵抗化についても一定の成果を得た。これらの成果は，電子デバイス／回路形成における下地基板の選択肢を飛躍的に広げることに貢献する。