Contact barriers modulation of graphene/β-Ga2O3 interface for high-performance Ga2O3 devices

• Published in: Applied surface science 2020-10, Vol.527, p.146740, Article 146740
• Main Authors: Yuan, Haidong, Su, Jie, Guo, Rui, Tian, Ke, Lin, Zhenhua, Zhang, Jincheng, Chang, Jingjing, Hao, Yue
• Format: Article
• Language: English
• Subjects: Density functional theory; Graphene; Ohmic contact; Schottky barrier; β-Ga2O3
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2020.146740

Modulating the thickness of graphene, interlayer distance and external electric-field for graphene/Ga2O3 are easy to eliminate the tunneling and Schottky barrier, and then to realize high performance β-Ga2O3 optoelectronic. [Display omitted] •A small n-type Schottky barrier height (SBHn) exists in the graphene/Ga2O3 contact.•SBHn-to-SBHp transition can be realized by applying positive external E-field.•Three methods can realize the SBHn-to-Ohmic transition for graphene/Ga2O3 interface.•The interfacial dipole and potential step are the main factors for the SBH. The ultra-wide-gap β-Ga2O3 has been regarded as a promising material for next-generation power electronic and deep-ultraviolet (UV) photodetectors. Exploring a suitable electrode is vital for realizing high performance β-Ga2O3 based nanodevices. Herein, the structural and contact properties of graphene/Ga2O3 interfaces are tuned and investigated by using the first-principles calculations. Results show that the small n-type Schottky barrier of about 0.07 eV for the graphene/Ga2O3 interface with weak interlayer interaction is irrespective of the interface stacking arrangement. Moreover, the intrinsic electronic property of Ga2O3 is well preserved in the interface. More interestingly, the n-type Schottky barrier to Ohmic contact transition can be obtained by shorting the interlayer distance, or increasing the graphene layers or applying a negative external electric field for the interface. Moreover, applying a large positive external electric field can realize the p-type Schottky barrier to Ohmic contact transition for graphene/Ga2O3 interface. These results are uncovered by analyzing the interfacial dipole and potential step of graphene/Ga2O3 interface, and expected to enhance the application potential of graphene electrode in the β-Ga2O3 based electronic and optoelectronic devices.