Effect of laser irradiation on structural, electrical, and optical properties of p-mercury cadmium telluride

Single crystals of p-Hc1−xCdxTe (x=0.16) were grown by the Bridgeman technique. The bulk single crystals were irradiated with laser pulse of various energy densities. A pulsed laser (Nd:YAG) capable of producing 10-ns pulses of 0.53 μm wavelength (frequency doubled) with varying energy densities (2–50 mJ/cm2) was employed. dc conductivity and Hall coefficient measurements were made on the single crystal using the Van der Pauw technique in the temperature range 77–300 K for both as-grown and laser-irradiated samples. Also the x-ray diffraction pattern and transmission measurements of the samples were taken at room temperature. Electrical studies shows that the p-mercury cadmium telluride after the laser irradiation becomes n type and optical results show that the free-carrier concentration after laser irradiation increases sharply so that there is negligibly small transmission. The x-ray studies show that single crystal p-type samples after laser irradiation undergo structural changes as well, introducing phases of CdTe, Hg, and Te in the lattice.