Doping engineering is necessary in the preparation of high-performance devices based on ultra-wide bandgap semiconductors. However, we do not yet understand the impurity level properties and their effects on performance modulation of transition metal doped α-Ga₂O₃. Here, using first-principles calculations with a hybrid functional, we find that I_B and II_B transition metal dopants exhibit relatively lower formation energies with a theoretically high hole concentration compared with Mg dopant. However, the induced acceptor levels are so deep that the impurity levels are transformed into AX centers. Although such AX centers hinder the formation of p-type conductivity, they can increase the optical absorption, ranging from deep ultraviolet to infrared regions. For electron-rich doped α-Ga₂O₃, the donor levels go from deep to shallow, then turn into deep levels again and finally to relatively shallow again as the transition metal dopant goes from group III_B to VIII_B of the periodic table. Because ionic bonds are formed between O and a dopant (IV_B to V_B) with a raised d-orbital, covalent characteristics are observed for the O dopant (VI_B to VIII_B) bonds with evident d-orbital splitting. These results add new insights into the impurity levels of α-Ga₂O₃, but also reveal potential applications of transition metal dopants in α-Ga₂O₃.

掺杂工程是制备基于超宽带隙半导体的高性能器件所必需的。然而，我们还不了解杂质能级特性及其对过渡金属掺杂的α- Ga ₂ O _{3 的}性能调制的影响。在这里，使用混合泛函的第一性原理计算，我们发现 I _B和 II _B与镁掺杂剂相比，过渡金属掺杂剂表现出相对较低的形成能和理论上较高的空穴浓度。然而，诱导的受体能级如此之深，以至于杂质能级被转化为 AX 中心。虽然这样的 AX 中心阻碍了 p 型导电性的形成，但它们可以增加光吸收，范围从深紫外到红外区域。对于富电子掺杂的α -Ga ₂ O ₃，随着过渡金属掺杂剂从元素周期表的III _{B 族}到 VIII _B族，施主能级从深到浅，然后再次变为深能级，最后再次相对较浅. 因为在 O 和掺杂剂之间形成离子键 (IV _B到 V _B）具有升高的 d 轨道，对于具有明显 d 轨道分裂的 O 掺杂剂（VI _B至 VIII _B）键，观察到共价特性。这些结果增加了对α- Ga ₂ O ₃杂质水平的新见解，但也揭示了过渡金属掺杂剂在α- Ga ₂ O _{3 中的}潜在应用。