Papers by Keyword: Light Induced Diffraction Grating

Abstract: Free carrier dynamics has been studied in 4H- and 3C-SiC in a wide temperature range using time-resolved photoluminescence, free carrier absorption, and light induced transient grating techniques. Considerably high carrier lifetime was observed in 3C-SiC epitaxial layers grown on 4H-SiC substrates using hot-wall CVD with respect to previously reported values for 3C-SiC grown either on Si or on 6H-SiC substrates. The temperature dependences of carrier lifetime and diffusion coefficient for 4H- and 3C-SiC were compared. Shorter photoluminescence decay time with respect to free carrier absorption decay time was observed in the same 4H-SiC sample, while these techniques revealed similar trends in the carrier lifetime temperature dependencies. However, the latter dependences for hot-wall CVD-grown 3C layers were found different if measured by time resolved photoluminescence and free carrier absorption techniques.

Abstract: The electrical and optical techniques have been applied for investigation of carrier transport and recombination features in thick free-standing 3C-SiC layers. Temperature dependencies of Hall mobility, magneto-resistivity, and conductivity indicated presence of high potential barriers, up to 0.4 eV. The carrier mobilities and equilibrium densities were calculated in the barrier and inter-barrier regions. Contactless measurements of the excess carrier ambipolar mobility and lifetime at 1016-18 cm-3 injection levels revealed carrier scattering solely by phonons in 80 – 800 K range. A correlation between the temperature dependencies of carrier lifetime and ambipolar mobility pointed out that diffusion-limited surface recombination at extended defects contributes significantly to the carrier lifetime.