Title:
Raman spectroscopy for analysis of
silicon precursor layers for liquid
phase crystallized solar cells
/ by Suheir J. D. Nofal ; supervised by Dr. Othman Zalloum, Maurice Nuys.
Author:
Nofal, Suheir J. D, author.
Zalloum, Othman, supervisor.
Nuys, Maurice, co-supervisor.
Palestine Polytechnic University (Hebron, Palestine). Deanship of Graduate Studies and Scientic Research. Renewable Energy and Environment Research Unit .
General Notes:
Thesis (M. Sc. in Renewable Energy and Sustainability)--Palestine Polytechnic University (Hebron, Palestine), Deanship of Graduate Studies and Scientic Research, Renewable Energy and Environment Research Unit
, 2019.
Includes bibliographical references and index.
Amorphous silicon thin lms based solar cells have a low eciency comparing to
the conventional poly-crystalline silicon wafer based solar cells. To overcome the
eciency limitation, the attempt to crystallize the amorphous silicon thin layers
deposited by Plasma enhanced chemical vapor deposition (PECVD) on glass is
investigated. the crystallization process is based on zone-melting technology and
called liquid phase crystallization (LPC). Raman spectroscopy is used to analyze
the properties of the silicon thin layers that is deposited by PECVD process and
crystallized by LPC process; for better understanding of these processes. The
present thesis provides the possibility of engaging Raman spectroscopy as a characterization
method with MATLAB software as the analysis tool to investigate the
properties of thin silicon precursor layers for liquid phase crystallized solar cells.
The exported data after analysis has been plotted into two dierent categories;
depth proling as well as two-dimensional mapping. The rst category includes
three samples deposited on glass by plasma enhanced chemical vapour deposition
with dierent deposition parameters (e.g.: silane concentration, rf power, and
pressure) to investigate the in
uence of these parameters on having amorphous or
micro-crystalline structure, as well as hydrogen content and micro-structure parameters.
The rst sample has a c-Si structure with crystallinity changing with
depth. The other two samples have a-Si structures. All samples have nearly a
constant hydrogen content and micro-structure parameters with depth. Then, the
amorphous samples have been annealed to investigate the in
uence of annealing
on the structural order and hydrogen diusion. The rst one is thermally unstable,
only 0.50 m remains on glass after annealing. While the other is stable
and the whole thickness remains unchanged during annealing. All hydrogen has
been diused in both samples. Raman spectroscopy is a useful technique to create
data that can be plotted as depth proles for the crystallinity, structural order,
hydrogen content, and micro-structure parameters for PECVD deposited precursors;
hence gives a better understanding of the changes in these properties with
depth. PECVD parameters of the last sample (SiH4
ow rate of 6 sccm, H2
ow
rate of 12 sccm, pressure of 1mbar, rf power of 25 W, and heater temperature of
450 oC) have been taken as the standard, since they deposit an a-Si structure, that
is thermally stable after annealing among all samples. The second section includes
one sample, which has been deposited by electron beam deposition, cut into ve
small samples, and then crystallized by liquid phase crystallization with dierent
crystallization parameters (e.g.: laser scan speed and power) to investigate the
in
uence of these parameters on stress inside the crystallized precursors. Three
2D maps have been taken in grain boundaries, where c-Si peak is shifting to lower
wavenumbers; hence a tensile stress behavior along grain boundaries is mapped.
Two 2D maps have been taken in the middle of a crack, where the stress behavior
is varied between a tensile stress on one side of the crack and a compressive
stress on the other side. The last 2D maps have been taken at a crack tip, where
the crack starts at the surface but does not continue with depth. higher tensile
stress has been mapped from the glass side, which does not reach its threshold
value to form the crack yet. Raman spectroscopy is a helpful tool in investigate
the stress resulted in LPC-Si precursors for better understanding of LPC process.
LPC parameters of the rst sample (red laser beam of 808nm wavelength, substrate
temperature of 510 oC, laser speed of 1 mm/s, and power of 45W) have been
taken as the standard, since they produce a non-cracked precursor with minimu m
number of grain boundaries among all samples.
The electronic version is available in theses database \\ University of Jordan.
Includes abstracts in Arabic and English.
Subject:
Renewable energy sources.
Solar energy.
Solar cells -- Research.
Solar cells -- Materials.
Silicon solar cells
Raman spectroscopy
Dissertation Note:
Thesis (M. Sc. in Renewable Energy and Sustainability)--Palestine Polytechnic University (Hebron, Palestine), Deanship of Graduate Studies and Scientic Research, Renewable Energy and Environment Research Unit
, 2019.
Physical Description:
1CD-ROM : PDF.
Publication Date:
2019.