北海道大学与京都大学实测 α-氧化镓电子有效质量约为自由电子 40%、高于理论预测 25%，热导率约 19 瓦每米开尔文
日本北海道大学与京都大学研究团队在《ACS 应用电子材料》（ACS Applied Electronic Materials）发表研究。团队以雾化化学气相沉积法制备 α-氧化镓（α-Ga₂O₃）薄膜，并掺入不同量的锗以提供导电电子，测量薄膜的电子浓度、热电势等电学性质，进而估算电子有效质量。实测有效质量约为自由电子质量的 40%，高于理论预测的 25%；团队表示，这一差异可能是电子在 α-氧化镓中移动不如预期顺畅的部分原因。
团队同时测得薄膜热导率约为 19 瓦每米开尔文（W/m·K），且该数值在锗浓度增加时几乎不变，显示掺锗可改善电子输运而不显著改变热传导。α-氧化镓因可承受很强的电场，被视为下一代功率电子器件的候选材料。论文第一作者为 Hiromichi Ohta，DOI 为 10.1021/acsaelm.6c01639。
图中是研究人员在实验室中进行氧化镓等氧化物半导体材料生长研究
关联：香港大学团队制成兆瓦级超宽禁带半导体模块：氧化镓器件在 1000 伏与 1000 安下重复开关，峰值功率达 1 兆瓦
Hokkaido and Kyoto Universities Measure Electron Effective Mass in Alpha-Gallium Oxide at About 40% of a Free Electron, Above the 25% Theoretical Prediction
Researchers at Hokkaido University and Kyoto University in Japan, publishing in ACS Applied Electronic Materials, prepared thin films of alpha-gallium oxide (α-Ga₂O₃) using mist chemical vapour deposition and added varying amounts of germanium to provide conducting electrons. Measuring the films' electron concentration and thermopower, the team estimated the effective mass of electrons at approximately 40% of a free electron's mass, higher than the theoretically predicted value of 25%; the team said this difference could be part of the reason electrons move less easily through alpha-gallium oxide than expected.
The team also measured a thermal conductivity of approximately 19 watts per meter-kelvin, which remained almost unchanged even when the germanium concentration increased, showing that adding germanium can improve electron movement without significantly changing heat transfer. Alpha-gallium oxide can withstand very strong electric fields and is a candidate material for next-generation power electronic devices. The paper, by Hiromichi Ohta and colleagues, has DOI 10.1021/acsaelm.6c01639.
来源：ACS应用电子材料
发布：GSM·美国（发布链接）
图片来源：图中是研究人员在实验室中进行氧化镓等氧化物半导体材料生长研究。Wikimedia Commons — U.S. Air Force AFRL by Keith C Lewis, Public domain
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