Electrical transport and defect spectroscopy of free standing single crystal CVD diamond prepared from methane rich mixtures

Abstract

Transient photocurrent measurements in the Time-of-Flight(TOF)configuration were used to study the electrical transport in sigle crystalline diamond layers using a Nd:YAG - pumped OPO (2.7 nsec) laser pulse excitation source working at a wavelength of ∼ 218 nm. The amount of collected charge was measured and the hole and electron drift mobilities were determined at room temperature for natural IIa diamond and intrinsic single chrystalline CVD diamond samples. A variation of the laser intensity over several orders of magnitude enabled switching between the so-called "small signal TOF" and "space charge limited current"(SCLC) modes. Experiments were done using electrical fields in the range of 0.05-1.2 V/μm.