Study On Size,Temperature,and Pressure Effects Of Dielectric Constant For Semiconductor Materials

The temperature and pressure effects of the photoelectric proper ties of nanosemiconductors play an important role in the design,optimization,and application of precise modern optoelectronic devices.However,the available theoretical methods for the size,temperature,and pressure effects of dielectric constant and refractive index are complicated,time-consuming,and containing empirical parameters without clear physical indications.In this paper,the group Ⅳ,Ⅲ-Ⅴ,and Ⅱ-Ⅵ semiconductors are studied.The functional expressions of size,temperature,and pressure dependent dielectric constant and refractive index are established,based on the bond-order-length-strength theory and the local bond average approach by combining with the core-shell configuration model.The Debye temperature,atomic cohesive energy,bond energy,energy density,and bulk modulus for semiconductors are obtained quantitatively.The relevant physical mechanisms are revealed,specifically as follows:(ⅰ)The size dependent dielectric constant and refractive index of semiconductors are established.The physical mechanism of size dependence is revealed: the pinning effect of chemical bonds on the surface of materials and the surface to volume ratio of nanoparticles dominate the size effect of dielectric constant and refractive index of semiconductors.(ⅱ)The temperature dependent dielectric constant and refractive index of semiconductors are established and the Debye temperature and atomic cohesive energy are obtained.The physical mechanism of temperature dependence is revealed: the Debye temperature determines the width of the non-linear part and the atomic cohesive energy determines the slope of linear part at high temperatures of the dielectric constant and refractive index curves.(ⅲ)The pressure dependent dielectric constant and refractive index of semiconductors are established and the energy density,bond energy,and bulk modulus are obtained.The physical mechanism of pressure dependence is revealed: the bulk modulus determines the nonlinear range at low pressures and the energy density determines the linear slope at high pressures in the pressure dependent dielectric constant and refractive index curves.In summary,in this article,the size,temperature,and pressure effects of dielectric constant and refractive index of semiconductors are studied systematically based on the bond-order-length-strength theory and local bond average approach.The physical mechanism of dielectric constant and refractive index changing under multi-field effects are revealed;the relevant physical parameters of semiconductors are obtained quantitatively.