Numerical simulation of the dynamics of phase transitions in CdTe induced by irradiation with nanosecond pulses of an excimer laser

Stability of a cadmium mercury telluride single-crystal structure during thermal conductivity measurements by the laser flash technique

“…To analyze the heating process in more detail, we used the approximation based on the numerical solution of a one dimensional thermal conductivity equation with the corresponding initial and boundary conditions, as was done, e.g., for CdTe in [11]. The calculations showed that, when high power short laser pulses are used, the absorbed energy exceeds the values necessary for melting the irradiated material, the temperature in the irradiation zone exceeds the melting level, and the distance from the zone boundary and the crystal area with a measuring temperature of 503 K is no more than 10-20 μm.…”

Acoustic response to the action of nanosecond laser pulses on an In/CdTe thin-film heterostructure

“…Due to the laser induced evaporation of indium atoms in air, sig nificant cooling of the surface takes place; in this case, the heat flux from the In surface can be written as Q = L In J In , where the mass density flux of evaporated atoms is J In (T) ~ P pairs (T) [18,19]; M is the atomic mass and L In is the latent heat of evaporation of indium. It should be noted that earlier we found by mathe matical modeling [3] that an In film with a thickness h In = 400 nm under irradiation by a ruby laser (with τ imp = 20 ns) in air begins melting at E = 16 mJ/cm 2 .…”

Dependence of the CdTe Melting Threshold on the Pulse Duration and Wavelength of Laser Radiation and the Parameters of Non-Equilibrium Charge Carriers

“…The mathematical modeling of phase transitions initiated in cadmium telluride by a pulsed laser radiation on the basis of the heat conductivity equation [4,11,16,17] is complicated due to the account for those parts of the optical radiation energy that are spent on the instant thermalization ( ≈ 10 −12 s) and the excitation of the electron-hole plasma followed by its diffusion and recombination. In work [18], this was done by making allowance for the energy components that are released at the thermalization of excited charge carriers immediately after their excitation and at the nonradiative bulk and surface recombinations.…”

“…= 300 nm, the absorption coefficient in CdTe is very high, and light is absorbed at a depth of about 10 nm. For example, for an excimer KrF laser ( = 248 nm, p = 20 ns, = 1.1 × 10 6 cm −1 ), the melting threshold th = 2.5 MW/cm 2 [3,4,16]. On the other hand, according to our calculations, th = = 2.71 MW/cm 2 , which is quite a reasonable value, because the reflectance has rather a high value of 0.46 at = 248 nm [22].…”