http://nopr.niscair.res.in/handle/123456789/13741 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/13784 Title: Qualitative analysis of small-signal modified Sziklai pair amplifier <br/> <br/>Authors: Pandey, Beena; Srivastava, Susmrita; Tiwari, Satyendra Nath; Singh, Jitendra; Shukla, Sachchida Nand <br/> <br/>Abstract: A small-signal modified Sziklai pair (complementary Darlington pair) amplifier is proposed with an additional biasing resistance in the circuit. The proposed amplifier produces significantly high voltage gain with narrow bandwidth. Poor response of conventional Darlington pair amplifiers at higher frequencies is found to be absent in the proposed amplifier circuit. Variations in voltage gain as a function of frequency and different biasing resistances, bandwidth and total harmonic distortion of the amplifier have also been studied. Proposed amplifier may be useful for various analog communication applications. <br/> <br/>Page(s): 272-276 http://nopr.niscair.res.in/handle/123456789/13783 Title: Saturated velocity model of MESFET in the presence of interface states and interfacial layer at the gate contact <br/> <br/>Authors: Chattopadhyay, P; Dutta, S <br/> <br/>Abstract: The saturated velocity model of a short channel MESFET has been extended by incorporating the effects of interface states and interfacial layer at the gate contact of the device. Simple analytical forms for the channel current, drain conductance and transconductance of the device are derived and they are found to be much sensitive to interface state density. The proposed model has been applied to compare the drain characteristics of Si, SiC and GaN MESFETs. For all three materials, the channel current has been found to decrease with drain voltage as the field across the channel exceeds the critical field required for velocity saturation. The decrease in the drain current yields a negative drain conductance and transconductance with respect to drain and gate voltage, respectively. The experimental results reported by the earlier researchers on GaN and SiC MESFETs are considered to compare the theory with experiment over the domain of velocity saturation. It has been found that the experimental results can be best explained on the basis of an energy distribution of interface states at the gate contact of both the devices. <br/> <br/>Page(s): 265-271 http://nopr.niscair.res.in/handle/123456789/13782 Title: Study of photoelectret effect in dysprosium doped zinc oxide <br/> <br/>Authors: Pandey, Nitin; Srivastava, Rajneesh Kumar; Prakash, S G <br/> <br/>Abstract: In the present work, photoelectret properties of ZnO and dysprosium doped ZnO have been studied. Dysprosium (Dy) has been mixed in ZnO by weight with varying proportion. ZnO:Dy (0.50%) exhibits maximum photopolarization. The variation of photoelectret charge with applied voltage, photopolarization time, dark depolarization time, intensity of illumination and wavelength of illumination has been studied. XRD and SEM studies show that particle size of ZnO and ZnO:Dy (0.50%) is the order of few hundred nano meters. <br/> <br/>Page(s): 260-264 http://nopr.niscair.res.in/handle/123456789/13781 Title: Effect of nanocrystalline silver impregnation on mechanical properties of diamond-like-carbon films by nano-indentation <br/> <br/>Authors: Paul, R; Dey, A; Mukherjee, A K; Sarangi, S N; Pal, A K <br/> <br/>Abstract: Nano-crystalline silver was embedded in diamond-like-carbon films by capacitatively coupled plasma chemical vapour deposition. Films with different nanocrystallite sizes and volume fractions of silver, deposited on glass and silicon (100) substrates have been studied by nano-indentation to evaluate the modulation of mechanical properties caused by silver incorporation into the diamond-like-carbon. Raman, atomic force microscopy, energy dispersive X-ray studies and X-ray diffractions have been utilized to determine the structural properties as well as the bonding environment in these films. Mechanical properties have been seen to be modulated significantly by nanocrystalline silver incorporation. <br/> <br/>Page(s): 252-259