Tackling Disorder in ?-Ga2 O3.
Tackling Disorder in ?-Ga2 O3.
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解决 α-Ga2 O3 中的紊乱。
DOI：
10.1002/adma.202204217
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Ratcliff LE
中科院分区：
文献类型：
--
作者：
Ratcliff LE
Ga 2 O3及其多晶型物越来越受到人们的关注。多晶型氧化物系统，如Ga 2 O3丰富的结构空间提供了潜在的电子结构工程，这是特别感兴趣的一系列应用，如电力电子。γ-Ga 2 O3由于其固有的无序性和由此产生的复杂的结构-电子-结构关系，在合成、表征和理论方面提出了特别的挑战。在这里，密度泛函理论与机器学习方法相结合，筛选了近一百万个潜在的结构，从而开发了一个强大的γ相原子模型。理论结果与表面和体积敏感的软和硬X射线光电子能谱，X射线吸收光谱，椭圆偏振光谱，和光致发光激发光谱实验代表的占用和未占用状态的γ-Ga 2 O3进行了比较。在室温下，从光谱椭圆偏振仪发现在5.1 eV处的第一个强吸收的开始，这与通过光致发光激发光谱获得的在5.17 eV处的激发最大值很好地一致，其中后者在5 K时移动到5.33 eV。这项工作在处理复杂的无序氧化物方面取得了飞跃，是探索如何从局部配位和整体结构方面理解其电子结构的关键一步。
Ga2O3and its polymorphs are attracting increasing attention. The rich structural space of polymorphic oxide systems such as Ga2O3offers potential for electronic structure engineering, which is of particular interest for a range of applications, such as power electronics. γ‐Ga2O3presents a particular challenge across synthesis, characterization, and theory due to its inherent disorder and resulting complex structure–electronic‐structure relationship. Here, density functional theory is used in combination with a machine‐learning approach to screen nearly one million potential structures, thereby developing a robust atomistic model of the γ‐phase. Theoretical results are compared with surface and bulk sensitive soft and hard X‐ray photoelectron spectroscopy, X‐ray absorption spectroscopy, spectroscopic ellipsometry, and photoluminescence excitation spectroscopy experiments representative of the occupied and unoccupied states of γ‐Ga2O3. The first onset of strong absorption at room temperature is found at 5.1 eV from spectroscopic ellipsometry, which agrees well with the excitation maximum at 5.17 eV obtained by photoluminescence excitation spectroscopy, where the latter shifts to 5.33 eV at 5 K. This work presents a leap forward in the treatment of complex, disordered oxides and is a crucial step toward exploring how their electronic structure can be understood in terms of local coordination and overall structure.