Fabrication of textured poly-crystalline silicon films from amorphous-silicon (a-Si) films using a line beam is
investigated. The mechanism of laser annealing and simultaneously form a nano-textured surface using an Nd3+: YAG
laser at a wavelength of 355 nm with a line beam is discussed. Amorphous-Si films coated on glass and crystalline
silicon substrates were treated with different laser fluence from 100 to 600 mJ/cm2 and with 90% beam overlap. The
crystallization and texturization characteristics were analyzed through SEM, Raman Spectroscopy, AFM, resistance and
absorbance measurements. Generation of polycrystalline textured peaks was confirmed with different characterization
methods and compared with the results of the conventional circular beam. This approach of line beam with increase in
the scanning speed will allow the faster production of polycrystalline silicon from a-Si for photovoltaic application.
Efficient doping of amorphous silicon(a-Si) is a key issue in the field of photovoltaic applications. In this paper an
attempt has been made to produce a highly highly textured Sb doped a-Si. The a-Si were coated with Sb to a thickness
of 200nm using vacuum evaporation method and treated with an Nd:YAG laser of 355nm with a threshold fluence of
460mJ/cm2 by overlapping the laser spots to 90% of its size. The samples are retretaed with a low laser fluence of
230mJ/cm2 respectively so as to crytsallize and diffuse the Sb on to the surface and to activate the dopant. The laser
doped and subequently laser textured samples were analysed through Scanning Electron microscope (SEM), X-ray
diffraction (XRD) & Atomic Force Microscope(AFM).The traces of SiSb in the XRD peak with improved surface
roughness were observed on the laser doped samples. This represents that the dopants are highly diffused on the a-Si.
A micro-electro-discharge machine (Micro EDM) was developed incorporating a piezoactuated direct drive tool feed
mechanism for micromachining of Silicon using a copper tool. Tool and workpiece materials are removed during Micro
EDM process which demand for a tool wear compensation technique to reach the specified depth of machining on the
workpiece. An in-situ axial tool wear and machining depth measurement system is developed to investigate axial wear
ratio variations with machining depth. Stepwise micromachining experiments on silicon wafer were performed to
investigate the variations in the silicon removal and tool wear depths with increase in tool feed. Based on these
experimental data, a tool wear compensation method is proposed to reach the desired depth of micromachining on silicon
using copper tool. Micromachining experiments are performed with the proposed tool wear compensation method and a
maximum workpiece machining depth variation of 6% was observed.
In the present work the scope of using micro-electro discharge machining (micro-EDM) technique to generate metalnanoparticles
is studied and thermal conductivity of the fluid with particles generated using micro-EDM is characterized.
In the experiment, aluminum workpiece is machined with an aluminum tool electrode in deionized water. 40 to 96 V is
applied for machining with pulse-on duration being varied between 10 and 100 microseconds. The particle count analysis
reveals that low voltage and high pulse-on duration favors formation of smaller sized particles, as predicted by the
developed model. A thermal conductivity measurements show 4% rise in thermal conductivity with the sample (0.004%
by wt. in deionized water) produced by micro-EDM setup.
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