Dielectric function models for describing the optical properties of hexagonal GaN

Abstract

Articles you may be interested inTemperature dependent dielectric function and the E 0 critical points of hexagonal GaN from 30 to 690 K AIP Advances 4, 027124 (2014); 10.1063/1.4867094Optical constants of cubic GaN/GaAs(001): Experiment and modeling Several different models have been employed for modeling the dielectric function of hexagonal GaN in the range from 1 to 10 eV. Models are compared in terms of number of parameters required, intricacy of model equations, and possibility of accurate estimation of important physical parameters, such as energies of critical points and exciton binding energies. Shortcomings and advantages of each model are discussed in detail. Excellent agreement with the experimental data for GaN has been achieved with three of the investigated models. It has also been shown that an assumption of adjustable broadening instead of a purely Lorentzian one improves the agreement with the experimental data and enables elimination of excessive absorption below the gap which is inherent to the models with Lorentzian broadening.

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“…The difference in slope in the transparent region is likely due to slight differences in the models used for underlying layers, including the GaN refractive index which is known to have some variation among the existing measurements. [59][60][61][62] The absorption edges show similar slopes between the two curves and are in good agreement.…”

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Machine learning dielectric screening for the simulation of excited state properties of molecules and materials

“…Several model dielectric functions have been proposed to speed-up the solution of the BSE for solids over the years. 48,[87][88][89][90][91][92][93] Recently, Sun et al 48 proposed a simplied BSE method that utilizes a model dielectric function (m-BSE). The authors used the model of Cappellini et al 91 with an empirical parameter, which they determined by averaging the values minimizing the RMSE between a model dielectric function and that obtained within the RPA for Si, Ge, GaAs, and ZnSe.…”