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Thin films of cuprous iodide (CuI), which is expected to be used in solid-state dye-sensitized solar cells as a hole conductor, were formed by spin coating and subsequent annealing. The effects of the annealing conditions on the electrical properties of the CuI films were investigated by resistivity and Hall-effect measurements. The CuI films showed p-type conduction with resistivities of 0.3-5 V cm, carrier concentrations of 1 Â 10 18 -1 Â 10 19 cm À3 and mobilities of 0.5-2 cm 2 V À1 s À1.It was found that the resistivities of the films annealed in air were slightly lower than those annealed in an Ar atmosphere because the carrier concentrations were higher in the former than in the latter. An increase in the mobility with the rise of annealing temperature was observed in the films annealed in Ar. However, annealing in air at high temperatures oxidized CuI to CuO.

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Cathodic electrodeposition of CdTe films was studied using aqueous ammonia-alkaline electrolytic baths (pH 10.7; temperature 343 K) in which Cd(II) and Te(IV) species were dissolved to form Cd(NH 3 ) 4 2ϩ and TeO 3 2Ϫ ions, respectively. From the solution, 60 mM Cd(II)Ϫ10 mM Te(IV)Ϫ4.0 M NH 3 Ϫ1.0 M NH 4 ϩ (M ϭ mol dm Ϫ3 ), a flat and smooth polycrystalline CdTe film (thickness, ca. 1 m) with nearly stoichiometric composition was deposited at a constant cathode potential, ranging from Ϫ0.70 to Ϫ0.30 V vs. SHE, whereas dendrite CdTe accompanying elemental cadmium was obtained at Ϫ0.80 V. The deposition behavior was fully explained by an underpotential deposition mechanism taking the calculated redox potentials of Te 0 /Te IV O 3 2Ϫ and Cd 0 /Cd II (NH 3 ) 4 2ϩ pairs into consideration. During electrodeposition of nearly stoichiometric crystalline CdTe, the current density was decreasing monotonously.

The electrical properties of polycrystalline CdTe layers electrodeposited from ammoniacal basic electrolytes were examined by resistivity and Hall effect measurements. As-prepared CdTe layers electrodeposited in the dark and under illumination were both found to be p-type with resistivity of 10 7 -10 9 ⍀ cm, carrier density of 10 9 -10 11 cm Ϫ3 , and mobility ca. 1 cm 2 V Ϫ1 s Ϫ1 . By decreasing the Cd͑II͒ concentration of the electrolytes, the Cd content of the CdTe layer slightly decreased and the carrier density increased correspondingly, whereas deposition potential did not affect the electrical properties. The temperature dependence of the resistivity revealed that the activation energy of conductivity was 0.67 eV, which suggested that the small carrier density was attributed to a compensation effect of semiconducting CdTe compound.