Abstract
With a direct bandgap, two-dimensional (2D) ZnSe is a promising semiconductor material in photoelectric device fields. In this work, based on first-principles methods, we theoretically studied the modulation of the Schottky barrier height (SBH) by applying horizontal and vertical strains on graphene/ZnSe heterojunction. The results show that the inherent electronic properties of graphene and ZnSe monolayers are both well-conserved because of the weak van der Waals (vdW) forces between two sublayers. Under horizontal strain condition, the n(p)-type SBH decreases from 0.56 (1.62) eV to 0.21 (0.78) eV. By changing the interlayer distance in the range of 2.8 Å to 4.4 Å, the n(p)-type SBH decreases (increases) from 0.88 (0.98) eV to 0.21 (1.76) eV. These findings prove the SBH of the heterojunction to be tuned effectively, which is of great significance to optoelectronic devices, especially in graphene/ZnSe-based nano-electronic and optoelectronic devices.
Highlights
Ever since graphene was exfoliated experimentally in 2004 Novoselov et al (2004), owing to its unique advantages, such as high charge mobility at room temperature and excellent Hall effect Novoselov et al (2005), Zhang et al (2005), it has attracted many theoretical and experimental attentions (Olabi et al, 2021; cao et al, 2018; Wang et al, 2020; Niu et al, 2020)
ZnSe as a zero bandgap material was not well-developed in graphene photonics and optoelectronics (Bonaccorso et al, 2010)
Our findings indicated the Schottky barrier height (SBH) of graphene/ZnSe could be effectively tuned by applying horizontal strain and vertical strain, which has potential applications in nano-mechanics, transistors, piezoelectric, and optoelectronics applications
Summary
Ever since graphene was exfoliated experimentally in 2004 Novoselov et al (2004), owing to its unique advantages, such as high charge mobility at room temperature and excellent Hall effect Novoselov et al (2005), Zhang et al (2005), it has attracted many theoretical and experimental attentions (Olabi et al, 2021; cao et al, 2018; Wang et al, 2020; Niu et al, 2020). In recent years, the 2D vdW heterojunction has attracted extensive attention in the field of electronic and optoelectronic devices (Zhang et al, 2020a; Guo et al, 2020; Zhu et al, 2021). How to tune the charge transfer and other electronic properties of the graphene/ZnSe interface? Many studies on graphene-based vdW heterojunction have been published Georgiou et al (2012), Si et al (2016), Qiu et al (2020), the electronic properties of the graphene/ZnSe heterostructure have not been clearly understood yet, as well as the SBH tunability under horizontal and vertical strain. Our findings indicated the SBH of graphene/ZnSe could be effectively tuned by applying horizontal strain and vertical strain, which has potential applications in nano-mechanics, transistors, piezoelectric, and optoelectronics applications
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