Temperature Dependence Of Optical Properties Of Silicon And Gallium Arsenide: A First-Principle Study

Temperature places significant influence on optical properties of semiconductors. Excellent description of the influence of temperature on the optical response is desired both from a theoretical point of view regarding the better understanding of the microscopic mechanism of such effect, and from a practical point of view concerning the management of radiative heat transfer. Nowadays first-principle calculation has wide applications in predicting physical properties of materials especially at extreme conditions such as high-temperature. In this paper, based on density functional theory in the framework of first-principle calculation, we research on the temperature dependence of separately ultraviolet-visible and infrared spectrum of semiconductor silicon (Si) and gallium arsenide (GaAs).Taking into account both electron-phonon interaction and excitonic interband absorption transition, we propose a straightforward method to calculate the temperature-dependent ultraviolet-visible spectra of semiconductors in a first-principle manner. Thermal expansion effect and electron-phonon interaction are both considered, based upon which the temperature-dependent ultraviolet-visible spectra of Si at room temperature and elevated temperature are further calculated. Our calculation results are in good agreement with experimental data, which verifies the feasibility of our method.Starting from the first-principle calculation of phonon-phonon anharmonic interaction, we propose a method to calculate the temperature-dependent infrared spectra of polar semiconductors based on damped oscillator model. The shift and broadening of optical phonons at the center of the Brillouin zone of GaAs induced from anharmonic phonon-phonon interaction are calculated. Combining the complex self-energy of phonons and damped oscillator model, we obtain the temperature-dependent infrared spectra of GaAs. Our calculation results are in excellent agreement with experimental data. Using McMahon formula which is based on geometrical optics, we further propose a first-principle way to calculate the temperature-dependent infrared radiative properties of partially transparent selective absorbing film. Using the calculated temperature-dependent optical dielectric functions, we obtain the spectral emissivity of GaAs film in the infrared region. The influence of temperature and film thickness on infrared radiative properties is analyzed.