Dielectric and Raman spectroscopy of MWCVD diamond thin films

Abstract

M. HERNANDEZ-Vr:LEZ, F. FERNANDEZ GUTIERREZ Grupo de zeofitas y propiedades dieldtricas en sdlidos, Facultad de Fisica, Instituto Superior Pedagogico E. J. Varona, C. Libertad. Marianao. C. de la Habana. Cuba The dielectric properties of diamond thin films obtained on silicon substrates by microwave plasma-assisted chemical vapour deposition (MWCVD) have been measured in the frequency range from 0.1 to 103 kHz at different temperatures up to 150 °C. The experimental results have been discussed in terms of the many body theory for dielectric relaxation in solids. Dielectric parameters as well as the d.c. conductivity of the samples have been correlated with the morphology and diamond content in the films, respectively detected from scanning electron microscopy (SEM) and Raman spectroscopy. The calculated activation energies for the dielectric relaxation mechanism agree with those obtained from other measurement techniques used in the electrical characterization of diamond films.

The Effect of Increased Methane Flow Rate on Electronic Correlation of Amorphous Silicon Carbon (a-SiC: H)

“…The optical gap width of the p-type a-SiC: H layer can also be obtained larger in the presence of carbon, besides that the presence of the amount of hydrogen also affects the optical gap increase, so it is often used as a transparent layer that is doped in solar cell applications, sensors, and electrolysis [6][7][8]. Increasing the width of the optical gap with the presence of carbon in the network layer of the p-type a-SiC: H followed by a worsening of its electrical properties and increased disorder [9][10][11]. The presence of carbon can increase the width of the state density in the tail region of the energy band, which can decrease the drift mobility thus worsening the electrical properties, whereas the reduction in disorder is thought to be due to the presence of trigonal C=C sp 2 in the sp 3 tetrahedral amorphous network [12][13].…”