In this work, we consider systematically the influence of uniaxial strain and external electric field $E$ on electronic properties of a monolayer InSe using ab-initio approach based on density functional theory. Our calculations indicate that the monolayer InSe has a medium indirect energy bandgap of 1.38 eV at equilibrium. The calculated results also demonstrate that we can adjust the bandgap of the monolayer InSe by strain engineering or electric field. The bandgap of the monolayer InSe changes dramatically when the uniaxial strain is applied. Especially, under the compressed uniaxial strain, an indirect–direct bandgap transition has been observed at certain elongations. Within the electric field magnitude $E$ range from 0 to 5 V/nm, the calculated results show that the negative electric field changes the bandgap of the monolayer InSe up to 23% while the positive electric field effect on its bandgap is negligible.

在这项工作中，我们系统地考虑了单轴应变和外部电场的影响 $E$密度泛函理论的从头算方法研究单层InSe的电子性质 我们的计算表明，单层InSe在平衡时具有1.38 eV的中等间接能带隙。计算结果还表明，我们可以通过应变工程或电场来调整单层InSe的带隙。当施加单轴应变时，单层InSe的带隙会发生巨大变化。特别是，在压缩的单轴应变下，在某些伸长率下观察到了间接-直接的带隙跃迁。内电场强度$E$ 范围为0至5 V / nm，计算结果表明，负电场将单层InSe的带隙改变高达23％，而正电场对其带隙的影响可以忽略不计。