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CVD diamond films with nitrogen content varying from 10 ppm to 132 ppm have been studied by electron spin resonance (ESR), light-induced ESR (LESR) as well as spin-dependent conductivity (SDC). Two characteristic signals have been observed. A carbon-related defect line with g = 2.0029 ± 0.0002 and width 4 ± 1 G, is observed in ESR, LESR and SDC. The intensity of this line measured by ESR increases linearly with nitrogen content. For low-defect-density samples, or after illuminating the high-defect-density samples with UV light, a second signal is observed both in ESR and LESR, but not in SDC, with a central line at g = 2.0024 ± 0.001 and width 0.2 ± 0.1 G and related hyperfine satellites ≈30 G away from the central line. This line is assigned to isolated substitutional nitrogen, the so-called P1 center. The density of N-related paramagnetic states is strongly affected by illumination and heat treatments. Spin-dependent conductivity measurements show that the dark conductivity at room temperature in CVD-diamond is dominated by hopping at the g = 2.0029 defects.

Investigations of polycrystalline chemical vapor deposited diamond films by electron‐spin‐resonance (ESR), light‐induced (L)ESR, and the constant photoconductivity method have identified dispersed substitutional nitrogen (P1 center) as the main paramagnetic form of N incorporated in the CVD diamond. The density of N‐related paramagnetic states is strongly affected by illumination and heat treatment. It is found that the P1 center in CVD diamond gives rise to a deep donor state about 1.5 eV below the conduction band.

Capacitance–voltage measurements have been performed on deuterated boron-doped synthetic-type IIb diamond. They demonstrate the electrical passivation of the boron acceptors, which was manifested by a persistent decrease in capacitance after deuteration. The capacitance–voltage dependence is explained by means of a two-layer depletion width model.

Capacitance–voltage (CV) and deep level transient spectroscopy (DLTS) experiments are applied to explore various properties of boron-doped type IIb high-pressure high-temperature diamond and of homoepitaxially grown boron-doped CVD diamond: contact properties of Al contacts, acceptor density determination, energy distributions and densities of compensating defects and the interaction of boron acceptors with atomic hydrogen (deuterium). Two distinct excitation energies at 0.9 and 1.25 eV are detected by DLTS and optically excited DLTS. We propose a defect/acceptor model where holes are optically excited from defects 1.25 eV above the valence band edge either into ionized boron acceptors at 0.36 eV above EV (optical excitation ≈0.9 eV) or directly into the valence band (photon energy ≥1.25 eV). We also discuss the decrease of the capacitance after deuteration as detected by CV measurements based on deuterium–boron complex formation.

Hall experiments on a series of microcrystalline, microcrystalline amorphous, amorphous and crystalline silicon samples with various defect densities are presented and discussed. Normal signs of the Hall effect in boron- and phosphorus-doped hydrogenated amorphous silicon have been observed. We interpret these results as due to a small volume fraction of nanocrystalline silicon, which falls below the detection limit of Raman experiments. Hydrogenated amorphous silicon, prepared under conditions far from microcrystalline growth, shows the known double-sign anomaly. On the other hand, sign reversals in crystalline silicon in which disorder was increased by silicon implantation up to apparently complete amorphization, were not found.

Pulsed interference laser crystallization of amorphous silicon has been applied to produce polycrystalline silicon thin films with grain sizes exceeding 5 µm. It has been achieved by shifting the samples through the interference pattern, with steps of typical 100 nm width. Grain sizes have been investigated by atomic force microscopy (AFM). The grains show quadratic shapes with a typical length of the applied interference period (5 µm) and width around 1.5–2.5 µm.