Graphene‐based vertical stacking heterojunction has attracted more and more attentions in optoelectronics, nanoelectronics, and spintronics field. A low Schottky barrier height (SBH) or a low‐resistance ohmic contact is desired in practical applications. In our current study, we have systematically investigated the interfacial characteristics of graphene/As₂S₃ heterojunction by using first‐principles calculations. The results indicate that the intrinsic electronic properties of graphene and As₂S₃ are changed little after contacting. The Bader charge analysis indicates that the transferred amounts of electrons from As₂S₃ to graphene decrease with the vertical electric field ranging from −0.5 to +0.5 V/Å. Consequently, when the electric field value is more negative than −0.2 V/Å, the heterojunction maintains a p‐type Schottky contact and transforms to n‐type Schottky contact once the external electric field is modified from −0.2 to +0.5 V/Å. Finally, an ohmic contact type can be formed if the external electric field is larger than +0.5 V/Å. In addition, the optical absorption of the As₂S₃/graphene interface is significantly enhanced after contacting. Our findings imply that the SBH is tunable, which is significantly meaningful in the nanoelectronic field‐effect transistors.

中文翻译：

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石墨烯/ As2S3界面中外部电场引起的肖特基-欧姆接触跃迁：基于第一性原理的研究

基于石墨烯的垂直堆叠异质结在光电子，纳米电子和自旋电子学领域引起了越来越多的关注。实际应用中需要低肖特基势垒高度（SBH）或低电阻欧姆接触。在我们目前的研究中，我们通过第一性原理计算系统地研究了石墨烯/ As ₂ S ₃异质结的界面特性。结果表明，石墨烯和As ₂ S ₃的固有电子性质在接触后几乎没有变化。Bader电荷分析表明，As ₂ S ₃中电子的转移量石墨烯在垂直电场范围为-0.5至+0.5 V /Å时降低。因此，当电场值大于-0.2 V /Å负时，一旦外部电场从-0.2变为+0.5 V /Å，异质结将保持ap型肖特基接触，并转换为n型肖特基接触。最后，如果外部电场大于+0.5 V /Å，则可以形成欧姆接触型。另外，接触后，As ₂ S ₃ /石墨烯界面的光吸收显着增强。我们的发现表明SBH是可调的，这在纳米电子场效应晶体管中具有重大意义。