Electrical Properties of Cadmium Sulphide Thin Films Prepared by Chemical Bath Deposition Technique: A Review

Dr. Vaibhav Jain

HOD and Associate Professer, DAV (PG) College, Bulandshahr, UP, India

In this work I tried to summarize some electrical properties of CdS thin films prepared by Chemical Bath Deposition (CBD) technique. CBD is very easy and cost effective. I focused on semiconductor type, resistivity and carrier mobility of CdS thin films. There is a good agreement in previous workers for these properties. They agreed that CdS is n type semiconductor and resistivity decreases while carrier mobility increases due to annealing of CdS thin films.

Keywords: Chemical Bath Deposition (CBD) technique, Semiconductor type, Resistivity and Carrier mobility.

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The Study of Channel Thermal noise in MOSFETs

Dr. V.P. Singh

Associate Professor, D.J. College Baraut, U.P., India.

In the present paper we studied experimentally the channel thermal noise in MOSFETs of short and long channel length at various drain to source voltage (V_ds) and various gate to source voltage (V_gs). We also plot graph between channel thermal noise (S_ID) Vs (V_ds) & channel thermal noise (S_ID) Vs gate to source voltage (V_gs). The result so obtained has good agreement with the theoretical data available in the literature. This proves the validity of our MOSFETs model.

Keywords: Channel thermal noise, MOSFETs model.

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The Study of Optical Band Gap of CdI₂ Films

Dr. V.P. Singh

Associate Professor, D.J. College Baraut, U.P., India

In this paper thin film of CdI₂ were grown on glass substrate at room temperature, elevated temperature by thermal evaporation  at a vacuum of about 10^-6 Torr using molybdenum boat. The optical absorption measurements were carried out in UV/VIS region using a (Shimadzu UV-260) spectrometer. The absorption coefficient  is calculated. The thickness of film (t) vs Energy bad gap (Eg) of CdI₂ is studied. Studies show both direct and indirect nature of band gap in conformation with existing theoretically calculated band structure in literature.

Keywords: thermal evaporation, Absorption coefficient, Energy bad gap.

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We present the investigations carried out on the effect of temperature on the performance of hydrogen phthalocyanine (H₂Pc)/fullerene (C₆₀) bilayer organic photovoltaic (OPV) devices. Prior to these investigations the thicknesses of the active layers were optimised to get the best performance. The optimised device had an efficiency of ~0.5% at 307 ^oK. The investigations on the best device showed that temperature has significant effect on the photovoltaic performance. Short circuit current density (J_sc) and fill factor (FF) decrease while open circuit voltage (V_oc) increases with reduction in temperature. In overall the efficiency first increases and then decreases with reduction in temperature. The reduction in J_sc and FF is because of the temperature dependent electronic properties of the organic materials. We have developed a model which shows that the built in voltage (V_bi) of the devices increases with reduction in temperature. The increment in V_oc with reduction in temperature has been attributed to the increment in V_bi.

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