A simple way to analyze infrared reflectivity spectra of p-type Hg 0.78Cd 0.22Te implanted in various conditions

Abstract

Different ion-implanted p-type Hg 0.78Cd 0.22Te samples were analyzed by infrared reflectivity in the 2–20 μm wavelength range. We show how to derive some characteristic values of the free carriers induced by ion implantation from simple models of the implanted samples. For low energy implantations (Al (320 keV)) an excess of electrons with concentration n + ≈ 5 × 10 17 cm −3 for doses 10 12 and 10 14 ions cm −2 is observed between the surface and the projected range R p of the ions, in agreement with the well-known change of type of the free carriers induced by the ion implantation in this kind of samples. High energy α particle (0.8 and 2 MeV, 10 14 ions cm −2) implantations lead to a pronounced inhomogeneous concentration of free electrons with n + ≈ 9.2 × 10 16 cm −3 between the surface and R p where a negligible amount of defects due to the nuclear energy loss is formed, and n + ≈ 1.6 × 10 17 cm −3 between R p and R p + Δ R p, Δ R p being the longitudinal straggling, where the defect production rate through the nuclear energy loss mechanism is maximum.