Light absorption process in a semiconductor infinite body with a cylindrical cavity via a novel photo-thermoelastic MGT model.

Photothermal spectroscopy is a method of measuring the optical absorption and thermal properties of semiconductor materials using high-sensitivity spectroscopic techniques. Heating occurs due to light, which is absorbed but not dissipated by emission. In this paper, a new model is provided that can be used to understand the process of optical thermal transfer and the interaction between elastic plasma waves and heat. The proposed photothermal model is described by the Moore–Gibson–Thompson heat equation. Using the proposed model, the thermal and photoacoustic effects in an infinite isotropic and homogeneous body with a cylindrical cavity of semiconductor material crossed into a fixed magnetic field and subjected to high-intensity laser heat flux were investigated. The inner surface of the cavity is considered to be traction-free, and the carrier density is photogenerated by a laser pulse heat flux that decays exponentially. The numerical calculations for the components of thermal stresses, displacement, temperature field, and carrier density are obtained using the Laplace transform approach. The propagation of heat, elastic, and plasma waves, as well as the distributions of each investigated field, were examined and explained. The comparison is also used to see how different thermal response features, such as thermal relaxation, laser pulse duration, and lifetime, affect the thermoelastic response. [ABSTRACT FROM AUTHOR]