The electrical transport properties of simultaneously deposited, B-doped homoepitaxial and polycrystalline diamond thin films have been evaluated by Hall-effect and resistivity measurements over a temperature range of 80–600 K. The same films were later characterized by scanning electron microscopy, secondary-ion-mass spectroscopy, and an oxidation defect etch. The study involved four sets of chemical-vapor-deposited diamond films with individual B concentrations ranging from 1.5×1017 to 1.5×1020 cm−3. In each of the four cases the mobility of the polycrystalline film was lower than that of the homoepitaxial film by 1–2 orders of magnitude over the entire temperature range. Polycrystalline films also incorporated 2–4 times more B, had 3–5 times higher compensation ratios, and displayed activation energies that were 0.05–0.09 eV lower than in the homoepitaxial films. Hopping conduction was observed in both types of films at low temperatures, but was enhanced in polycrystalline films as evident by higher transition temperatures. Preliminary efforts have been made to evaluate these results by considering the possible effects of crystal structure, compensation, impurity segregation, grain-boundary trapping, and impurity conduction.

The preparation of electrodeposited semiconductors for Hall effect measurements is complicated by the fact that these materials are, by necessity, attached to highly conducting substrates. As a result, methods were developed to reproducibly remove large area samples from their conducting substrates, and suitably prepared samples were used for temperature‐dependent Hall measurements and resistivity measurements. Apparatus was designed and built to routinely measure Hall voltages as low as 250 μV for source impedances up to 1012 Ω using films about 1 μm in thickness. Measurements were performed on numerous electrodeposited materials: normalCdTe , normalCdS , normalCdSe , and HgxCdfalse(1−xfalse)normalTe . Argon annealed electrodeposited normalCdTe was found to be consistently p‐type, with resistivity values typically 106–107 · Ω · cm p → n conversion of normalCdTe was achieved by diffusion of Cd at high temperature. HgxCdfalse(1−xfalse)normalTe was also p‐type, but had much lower resistivity and higher carrier concentration than normalCdTe . normalCdS and normalCdSe were both n‐type with carrier concentrations typically 1016 cm−3 and 1014–1016 cm−3, respectively.

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Doped CdSe thin films were electrodeposited onto indium-tin oxide (ITO) substrates that were pretreated with a thin layer of Se, Cd, or In. Hall effect and resistivity measurements were performed to determine the effects of doping on the resistivity, carrier concentration and carrier mobility. The data varied in a systematic fashion that correlated with the substrate treatment and doping procedures. Carrier concentrations ranged from 10 j ~to 10 ~ cm ', and the el ectrical resistivities were measured in the range of 1-> I x 10 ' ~l-cm. Hall effect mobilities were in the range of 1-50 cm~:/Vs. As doping levels increased, both resistivity and mobility decreased. Samples deposited on vapor treated ITO showed consistently high resistivities and moderate mobility values. When electrochemical treatments of ITO were used, the CdSe properties varied systematically with the amount of Cd or In e]ectrodeposited, exhibiting resistivities in the lower range and carrier densities in the higher range. The temperature dependent resistivity and Hall effect data were analyzed using the Seto-Baccarani model for polycrystalline semiconductors. This model assumes that the dominant transport mechanism is thermionic emission of carriers over the potential barriers that form at the intercrystalline grain boundaries.

The semiconducting properties of diamond make it a material of interest for the fabrication of active electronic devices. Device performance depends on the properties of the host diamond film and the device structure. Improvements in the electronic properties of chemical vapor deposited (CVD) diamond films and in device design are required for development of commercial diamond devices. Hall-effect and capacitance-voltage measurements have been used to assess the electronic quality of diamond films and to evaluate potential device materials and structures. Homoepitaxial, highly oriented and polycrystalline CVD diamond films have been deposited and characterized by variable-temperature Hall-effect measurements. The highest room temperature hole mobility measured in a homoepitaxial film was 1590 cm2 /V•s where the compensation was ∼2 × 1015 cm-3. These properties are now beginning to approach those of the best type IIb natural diamonds. In a comparison of homoepitaxial, highly oriented diamond film, and polycrystalline diamond films, the room temperature hole mobility was 1470, 229 and 70 cm2/V•s, respectively. This data provides further evidence that the alignment of the grains improves the transport properties of diamond films. Capacitance-voltage measurements have been performed on single crystal type lib diamond with metal-insulating diamond-semiconducting diamond and metal-oxi de-semiconducting diamond structures. Using a conductance versus frequency technique, the density of interface states was estimated to be ∼1012 cm-2eV-1 for both structures. Although optimization of these structures must still be performed, the ability to measure the interface trap density offers the opportunity to provide direct feedback to the device fabrication process so that the structure may be optimized.