OPTICAL AND ELECTRICAL-PROPERTIES OF 6H ALPHA-SIC IRRADIATED BY SWIFTXENON IONS

Single crystals of 6H alpha-SiC have been irradiated at GANIL accelera tor by 5.5 GeV xenon ions. Changes in microstructure of the material, studied by transmission electron microscopy (TEM) and high resolution electron microscopy (HREM), were previously reported and compared to o ther results obtained in neutron irradiated samples. The electrical pr operties of p-type material (p = 1.4 x 10(17) cm(-3)) were analyzed by means of in situ conductivity and Hall mobility measurements, up to a fluence of 1 x 10(13) Xe cm(-2). The hole mobility remains almost con stant up to 1 x 10(12) Xe cm(-2), and then decreases slowly. The carri er concentration first increases to reach 2.5 x 10(17) cm(-3), and the n decreases, Optical absorption is investigated after irradiation in s amples irradiated with 2 x 10(13) and 1 x 10(14) Xe cm(-2). The study of the variation of absorption coefficient alpha versus the wavelength shows that the band gap E(g) decreases from 2.78 eV before irradiatio n to 2.62 eV after the fluence of 2 x 10(13) Xe cm(-2), and even to 1 eV after 1 x 10(14) Xe cm(-2). According to this fact, the transmissio n band at 440 nm progressively disappears. These results are compared to previous ones obtained after electron irradiation.