The interesting properties of semiconductor materials have a wide field of application as thin-film components in various devices such as radiation filters, photosensors and some types of photovoltaic structures. CdS is a very interesting semiconductor material for its application in optoelectronic devices. As part of a polycrystalline solar cell, CdS acts as a window layer for solar radiation. On the other hand, efficient electronic components based in this material such as photodiodes or LDR photoresistors are produced and marketed. The optical and electrical properties of thin films of CdS synthesized by the chemical bath deposition technique (CBD) can be tuned by controlling growth parameters and / or post synthesis processing for doping with metals such as Cu, Ag and Al among others. In this work, CdS thin films doped with Cu were obtained through two stages. In the first one, a free ammonia CBD reactor was used. For the synthesis of the CdS simple film, reagents such CdCl2, Na3C6H5O, KOH and CH4N2S were used at 70°C, with a deposit time variation of 30, 60, 90 and 120 minutes. Subsequently in the second reactor, the films were doped by the SILAR technique at 24°C by immersion in an aqueous solution of CuSO4. For the optical characterization of the thin films, a UV-Vis HACH DR6000 spectrophotometer and Photoacoustic Spectroscopy were used, using a 900W Spectra-Physics model 66885 xenon lamp, an Oriel Cornerstone 130 monochromator and an MTEC 300 photoacoustic cell. With these techniques, absorption and transmission spectra in the range of 250 to 1200 nm were obtained, as well as the energy of the bandwidth of bandgap (Eg). The electrical properties such as the concentration of charge carriers and mobility, resistivity and electric conductivity, were determined using the HMS-3000 Hall effect measurement system. Likewise, the I-V curves were obtained and the TLM method was applied to measure the laminar resistance of the materials.
Share this page on your timeline