ELECTRONIC-PROPERTIES OF CVD AND SYNTHETIC DIAMOND

Transport and contact properties of synthetic IIb- and intrinsic chemi cal vapor deposition (CVD) -diamond films are discussed. The samples h ave been investigated by time-of-flight and transient photoconductivit y experiments using Cr/Au contacts. A hole depletion layer at the Cr/A u-IIb-diamond interface and an electron depletion layer al the Cr/Au-C VD-diamond interface is detected. The data indicate that our normally undoped CVD-diamond films are n-type semiconductors. In IIb diamond th e mobilities of electrons and holes have been measured, while in CVD d iamond no carrier transit can be detected due to the short Schubweg le ss than or equal to 1 mu m. Two trap levels located approximately 190 meV below the conduction band and 670 meV above the valence band are d educed. Electron spin resonance experiments demonstrate that these CVD films are highly defective, containing about 10(18) cm(-3) carbon rel ated defects (g = 2.0029).