Optical and electrical properties of indium monosulfide (InS) thin films

Indium monosulfide (InS) thin films were prepared by thermal evaporation onto quartz and glass substrates held at 473 K during the deposition process. The structural investigations showed that the obtained films have an amorphous nature. Energy dispersion X-ray spectroscopy analysis showed that they are stoichiometric. The optical constants, the electrical resistivity, as well as the space charge limited currents were studied. The obtained results indicate that InS thin films have nondirect allowed optical transitions with an energy gap of 1.94eV. The thermal activation energy of the charge carriers from the electrical resistivity measurements was found to be 0.84eV, which was confirmed by the space charge limited current technique. The trap density N-t was found to be 5.88 x 10(21) m(-3). (C) 2001 Elsevier Science Ltd. All rights reserved.