Browsing by Author "Das, N.K."

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Developing A Smart Control System Of Electrical Appliances By Computer Interfacing
(R&D Wing, MIST, 2011-02) Das, N.K.; BN, Capt. M.Ziauddin Alamgir; Das, C.K.; Hasan, M. M.; Rahman, M. M.; Alam, M. F.
The use of computer interfacing systems for controlling the device is spreading at an increasingly fast pace, with analogous wired system being substituted by computer interfaced systems alternatives in growing number of industries. As the technology progress many control system have been developed ranging from high end stuff to our common daily life. The main objective of this project is to develop a roadmap on communication and control technologies for distributed electrical equipments. Equipments located at any remote place can be monitored and controlled. The process is mainly to communicate between the two remote controlling device and setup connection between devices which are to be controlled. The main hallmark is to get access to the controlling section from any distance location in a convenient way and supervising the system accordingly. The speciality of this project is that the operator will able to control different devices at home/industry by using a single PC. An added advantage of this control system is that the operator will able to know the status of the device to be controlled from a remote place. Here, the algorithm of controlling any kind of electrical equipments is developed. The speeds of a DC motor are controlled as a test case and also monitor the voltage and current during different speed level of the motor.
The significance of bilayer window (CdS:O/CdS) on the performance of CdTe thin film solar cells
(Elsevier, 2024-09) Das, N.K.; Farhad, S.F.U.; Gupta, A.K. Sen; Ahamed, E.M.K. Ikball; Matin, M.A.; Amin, N.
Ultrathin and compact CdS:O/CdS bilayer window in CdTe solar cells has higher potential for enhanced p-type doping, reduced Te diffusion, and improved power conversion efficiency (PCE) compared to traditional single-layer CdS or CdS:O windows. In this effort, we used a two-gun RF sputtering equipment to deposit compact CdS:O (∼50 nm)/CdS(∼50 nm) bilayers onto the borosilicate and ITO-coated glass substrates at low temperature (≤250 °C). Intriguingly CdS:O/CdS bilayers retain its hexagonal {0002} preferential orientation but with around 10.58 % optical bandgap (Eg) increment compared to CdS (Eg ≈ 2.32 eV) of equal thickness (∼100 nm). Close-spaced sublimation (CSS) technique was used to deposit the CdTe thin film onto the CdS and CdS:O/CdS layers at 650 °C. The effect of CdS and CdS:O/CdS layers on the microstructural and morphological features of CdCl2-treated CdTe films were critically analyzed in revealing a promising {0001}/{111}-like partial-epitaxy presumably due to the preferential cubic CdTe growth along the <111> orientation. The CdTe films grown over a CdS:O/CdS layer exhibited smaller average crystallite and grain sizes than those grown over a single CdS layer. An essential finding was the formation of an optimal intermix layer of CdSxTe1-x, particularly evident in the CdTe films grown on the CdS:O/CdS bilayer. To comprehensively explore the effect of CdS:O/CdS window layers on PCE, complete CdTe solar cells were fabricated using three different window layers: CdS, CdS:O, and CdS:O/CdS, which are all considered as rudimentary as no layer optimization was performed. Notably, CdTe solar cell that incorporates the CdS:O/CdS bilayer window exhibited the most promising performance among all the tested rudimentary cells and corroborated the numerically simulated findings conducted by the SCAPS-1D simulator.