Atomic structure, electronic states, and optical properties of epitaxially grown β-Ga2O3 layers
Atomic structure, electronic states, and optical properties of epitaxially grown β-Ga2O3 layers
复制标题
DOI：
10.1016/j.spmi.2018.05.027
复制
发表时间：
2018-08-01
影响因子：
3.1
通讯作者：
Esin, A. A.
中科院分区：
文献类型：
--
作者：
Zatsepin, D. A.;Boukhvalov, D. W.;Esin, A. A.
生长了不同厚度的β-Ga 2 O3外延层，并用X射线光电子能谱（XPS）和光反射谱对其进行了表征。XPS电子结构图和价带谱表明β-Ga 2 O 3外延层的沉积时间与缺陷数量之间的关系。与直觉相反，与10和30 min时形成的最厚膜相比，2 min内形成的最薄膜（8 nm）几乎无缺陷。密度泛函理论模型预测，（几个eV）的形成能量的所有类型的缺陷，在散装β-Ga 2 O3和高能隙镓缺陷的形成，而不是在表面上的标准的氧化物氧空位的可替代性。β-Ga 2 O3的这种独特性可以用镓的小离子半径来解释，并且似乎是缺陷数量随生长时间增加的原因。
beta-Ga2O3 epitaxial layers of different thicknesses were grown and characterized by X-ray photoelectron (XPS) and optical reflectance spectroscopies. The XPS electronic structure mapping and the valence band spectra demonstrate the relationship between the time of deposition of the beta-Ga2O3 epitaxial layers and the number of defects. Counterintuitively, the thinnest films (8 nm) fabricated within 2 min were almost defect-free in contrast to the thickest ones formed at 10 and 30 min. Density functional theory modeling predicted rather high (several eV) formation energies of all types of defects in bulk beta-Ga2O3 and the energetic favorability of the formation of the interstitial gallium defects instead of the standard oxide oxygen vacancies on the surface. This uniqueness of beta-Ga2O3 could be explained by the small ionic radii of gallium and appeared to be the cause of the increase in the number of defects with the time of growth.