论文标题
测量和数值计算热导率，以评估蓝宝石在蓝宝石上生长的β-gallium氧化物薄膜的质量，并通过分子束外尾部生长的碳化物和碳化硅
Measurements and Numerical Calculations of Thermal Conductivity to Evaluate the Quality of β-Gallium Oxide Thin Films Grown on Sapphire and Silicon Carbide by Molecular Beam Epitaxy
论文作者
论文摘要
我们报告了一种方法，可以洞悉通过分子束外延（MBE）在C-平面蓝宝石和4H-SIC底物上生长的β-GA2O3薄膜的较低的热导率。我们将实验值与数值预测进行比较，以破译薄膜中边界散射和缺陷的影响。我们使用时域热素控表（TDTR）来执行实验，密度功能理论和Boltzmann传输方程进行热导率计算，以及用于TBC预测的弥漫性不匹配模型。实验热电导率的大约比针对相似大小的完美GA2O3晶体计算出的高3倍。在考虑存在晶界，炮和氧空位以及计算中堆叠断层的存在时，存在约1％的凝胶空位的晶体和106个断层/cm的堆叠断层密度是其热导电率更接近实验结果的晶体。我们的分析表明，GA2O3晶体中存在的不同类型的缺陷水平可通过减少这些缺陷来改善MBE生长样品的质量，从而产生具有较高导电性的材料。
We report a method to obtain insights into lower thermal conductivity of β-Ga2O3 thin films grown by molecular beam epitaxy (MBE) on c-plane sapphire and 4H-SiC substrates. We compare experimental values against the numerical predictions to decipher the effect of boundary scattering and defects in thin-films. We used time domain thermoreflectance (TDTR) to perform the experiments, density functional theory and the Boltzmann transport equation for thermal conductivity calculations, and the diffuse mismatch model for TBC predictions. The experimental thermal conductivities were approximately 3 times smaller than those calculated for perfect Ga2O3 crystals of similar size. When considering the presence of grain boundaries, gallium and oxygen vacancies, and stacking faults in the calculations, the crystals that present around 1% of gallium vacancies and a density of stacking faults of 106 faults/cm were the ones whose thermal conductivities were closer to the experimental results. Our analysis suggests the level of different types of defects present in the Ga2O3 crystal that could be used to improve the quality of MBE-grown samples by reducing these defects and thereby produce materials with higher thermal conductivities.
