Optical and electrical studies on MoBi2Se5 thin films prepared by Arrested Precipitation Technique (APT)

By R. M. Mane, R. R. Kharade, N. S. Patil and P. N. Bhosale

Abstract

The layered molybdenum chalcogenides and lattice structured bismuth chalcogenides are semiconductors which can be efficient electrodes in the realization of photo electrochemical solar cells. The bismuth chacogenides are thermoelectrically important materials which are used as thermoelectric coolers and sensors. The main advantage of molybdenum chalcogenide semiconductor is the prevention of electrolyte corrosion because of the photo transition involving non bonding d-d orbital of the Mo atoms. MoBi2Se5 thin films are prepared by simple and low cost arrested precipitation technique (APT). The growth kinetics of the films was studied and the deposition parameters such as bath concentration, bath temperature, time of deposition, PH of bath etc., are optimized. X-ray diffraction analysis of the films showed the highly textured MoBi2Se5 films with orthorhombic structure. Surface morphology studies by scanning electron microscopy (SEM) shows that the films are pinhole free and of device quality nature. EDAX spectrum of the surface composition confirms the nearly stoichiometric MoBi2Se5 thin films. Optical absorption spectra show band gap value 1.78eV. Conductivity measurements carried out at different temperatures and activation energy was calculated. The thermoelectric power measurements showed material to be n-type.

 

Key Words : X-ray diffraction, growth from solution, thin film, semiconducting ternary compounds.

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