Tailoring the structural and electronic properties of a graphene-like ZnS monolayer using biaxial strain

Abstract

Our First-principles Full-Potential Density Functional Theory (DFT) calculations show that a monolayer of ZnS (ML-ZnS), which is predicted to adopt a graphene-like planar honeycomb structure with a direct band gap, undergoes strain-induced modifications in its structure and band gap when subjected to in-plane homogeneous biaxial strain (δ). ML-ZnS gets buckled for compressive strain greater than 0.92%; the buckling parameter ∆ (= 0.00Å for planar ML-ZnS) linearly increases with increasing compressive strain (∆ = 0.435Å at δ = −5.25%). A tensile strain of 2.91% turns the direct band gap of ML-ZnS into indirect. Within our considered strain values of |δ| < 6%, the band gap shows linearly decreasing (non-linearly increasing as well as decreasing) variation with tensile (compressive) strain. These predictions may be exploited in future for potential applications in strain sensors and other nano-devices such as the nano-electromechanical systems (NEMS).

Strain-engineered band parameters of graphene-like SiC monolayer

“…We have used the Elk-code [23] and the Perdew-Zunger variant of local density approximation (LDA) [24] for our calculations, the accuracy of which has been tested in our previous works of other 2D crystals [9,10,[25][26][27][28]. The k-point grid size of 20 20 1 was used for structural and of 30 30 1 was used for band structure calculations using the Monkhorst-Pack scheme [29].…”

“…Recent experimental and theoretical studies on graphene [1][2][3] (a monolayer of carbon atoms in a two dimensional (2D) hexagonal lattice) have revealed many of its unique exotic properties promising a variety of novel applications, creating considerable interest in the study of other 2D crystals [4][5][6][7][8][9][10] of group IV elements, compounds of III-V and II-VI group elements. Density functional theory (DFT) based calculations [6][7][8][9][10] predict that the 2D crystals of SiC, GeC, BN, AlN, ZnO and ZnS adopt graphene-like planar 2D hexagonal structures, unlike the 2D hexagonal Si and Ge, which adopt quasi-2D buckled structures [11][12].…”

“…Density functional theory (DFT) based calculations [6][7][8][9][10] predict that the 2D crystals of SiC, GeC, BN, AlN, ZnO and ZnS adopt graphene-like planar 2D hexagonal structures, unlike the 2D hexagonal Si and Ge, which adopt quasi-2D buckled structures [11][12]. Since these predictions have already been confirmed for 2D Si [11], BN [4] and ZnO [13], the experimental synthesis of graphene-like SiC monolayer (MLSiC) is expected in near future.…”

Mechanical properties and stabilities of g-ZnS monolayers

“…12 The planar g-ZnS monolayers have a direct band gap over 2.0 eV (ref. 13 The 2D bulk modulus of g-ZnS monolayers is predicted to be 23.94 N m À1 using density functional theory calculations. 13 The 2D bulk modulus of g-ZnS monolayers is predicted to be 23.94 N m À1 using density functional theory calculations.…”

Hydrothermal synthesis of ternary ZnXCd1−XS–graphene and its photoelectric properties

“…Being promising in photocatalytic, biomedical, electrochemical, and optoelectronic applications, metal chalcogenide semiconductor nanomaterials composed of atoms from II and VI groups have attracted much attention in recent years [1][2][3][4][5]. As an important II-VI semiconductor, ternary alloy Zn X Cd 1-X S with band gap between 3.66 ev (for ZnS) and 2.44 ev (for CdS) can be tuned by the Zn/Cd ratios in the visible range.…”