Ni2S2−x thin lms with x = 0, 0.5, and 1 were prepared by chemical bath deposition technique. Amorphous structure was discovered by XRD for x = 1, while α-Ni7S6 and NiS phases were discovered for x = 0, and x = 0.5 respectively. SEM graphs of the studied lms have conrmed the XRD results. Optical band gap values increase from 0.845 to 0.912 eV, with increase of the composition x from 0 to 1. Activation energy values increase in the range from x = 0 to x = 0.5 and does not change for x = 1.

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Graphene has unique two-dimensional structure, high surface area, and remarkable chemical stability. Graphene oxide (GO) produced by the Hummers method was reduced to graphene by pulsed laser deposition (PLD). The graphene specimen in the form of a powder and a multilayered structure is studied. X-ray diffraction of graphene is interpreted to elucidate its short-range order and to calculate the number of layers of graphene. Electron diffraction and transmission electron microscope studies elucidate the short-range order nature of deposited graphene. The temperature dependence of the Seebeck coefficient (𝑆) indicates the carrier type reversal (CTR) from the 𝑛-to 𝑝-type, by starting from 60 ∘ C. CTR is affected by the applied voltage, frequency, and temperature. Distinct oscillations in the Seebeck coefficient thickness dependence are observed and attributed to the size quantization effect in graphene layers. The velocity, mobility, and electrical conductivity are measured and calculated to complete the transport properties of graphene. K e y w o r d s: structure, carrier type reversal, thermoelectric power, electrical conductivity.