The Effects Of Fabrication Processes On Isc And Voc Of Monocrystalline Silicon Solar Cell Characteristics
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Date
2011
Authors
Hassan Qa'eed, Motahher Abdallah
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
This thesis is concerned with the fabrication of a solar cell in NOR laboratory
using phosphorus and boron diffusions to measure the effect of the fabrication
processes on the monocrystalline silicon solar cell. To carry out this, the researcher
has employed a number of relevant theoretical concepts and equations.
The processes which were performed included thinning the wafer, diffusing
the boron to improve the back surface field (BSF), texturing the surface, diffusing
phosphorus to create the emitter, annealing, anti-reflection coating, metallization, and
edge shunt isolation. KOH solution was used and it played the role of texturing the
surface. Acidic solution was used and it played the role of thinning the wafer.
These processes were measured by easy and direct measurements of short
circuit current (Isc) and open circuit current (Voc). The short circuit current and open
circuit voltage were measured before and after each process, except for thinning the
wafer and (BSF) processes which include two groups of samples the first group is
measured with applying the process. The second group was measured without
applying the process. These electrical measurements were used as the main factors in
this study to examine the solar cell's output. The method of measurement shortens
the measurement time of characterization steps in the laboratory.
In this work, the average of Voc was 345 mV and 415 mV for the thick and
thin (< 200 μm thick) solar cell respectively; while, the average of Isc for the thick
and thin solar cell was 6.15 mA and 8.05 mA respectively. The average Voc with and
without apply BSF were 163 mV and 360 mV, respectively. Before the metallization
process, the average of Voc was 350 mV. However, it became 398 mV after the
metallization process. The average of Isc was 5.25 mA and 8.13mA before and after
the metallization process, respectively. In this research, the average of Voc before and
after the shunt isolation process was 412mV and 426 mV, respectively. While, the
average value of Isc increased from 8.9 mA to 9.7 mA due to the shunt isolation
process. The phosphorus diffusion depth in monocrystalline silicon solar cell cj was
2.457μm. The solar cell efficiency under optimal conditions was 9.51% and the fill
factor (FF) was 0.79. This work resulted in drawing a clear picture of the electrical
characteristics in each process independently.
Description
Keywords
The effect of the fabrication processes , on the monocrystalline silicon solar cell