| Indium selenide(InSe)is an emerging two-dimensional semiconductor material with excellent properties such as the highest carrier mobility among twodimensional materials,widely adjustable band gap values,good flexibility and strength.Therefore it has received extensive attention from researchers and shown great potential for applications in optoelectronics and flexible optoelectronics,etc.InSe has unique anisotropical optical properties,and its band edge optical transition dipole is out-of-plane oriented,which makes it insensitive to incident light perpendicular to the plane and reduces the optical performance of layer less InSe.In order to improve the optical properties of InSe,researchers have devoted a lot of relevant research efforts.In this thesis,we apply first-principle calculations and present a systematic theoretical study of the regulation of the optical properties of InSe in terms of electronic structure,optical properties,and geometrical morphology,and have achieved the following results:1.The establishment of theoretical model for optical response enhancement of bent InSe thin films.Due to the strong optical anisotropy of InSe,the enhancement of its optical response can be achieved by bending InSe thin films.By calculating and analyzing the electronic structure of layered InSe,we found that the optical transition B’,which has been neglected by researchers,plays an important role in determination of the optical response enhancement of InSe.Based on this finding,we modeled the photoluminescence process of bent InSe films and accurately calculated their optical absorption coefficients,established a theoretical model for the optical response enhancement of bent InSe films.Based on this model,we accurately simulated the optical response enhancement intensity of 1 to9-layer InSe films under incident light with different photon energies and incident angles.This work provides a valuable reference for future flexible optoelectronics applications of InSe.2.A theoretical model for the luminescence enhancement of regular protruding InSe films was established and the related experimental phenomena were explained.By covering the InSe films onto Si substrates etched with Si nanopillars in advance,the experimental collaborators produced regular bumps on the InSe films and found strong luminescence enhancement on the bumps.The theoretical computational simulations basically excluded the contribution of stress to the luminescence enhancement phenomenon.Based on the established photoluminescence model,we established a theoretical model of the luminescence enhancement on the bumps of InSe films by integration,and made a reasonable explanation for the luminescence enhancement phenomenon on the bumps of InSe films and predicted how to modulate the incident light energy to obtain greater luminescence enhancement. |
