Characterization of cdxsel_xs/cu2sp-n junction for solar cell application deposited by chemical bath deposition method
Loading...
Date
2014-07-30
Authors
Njeru, Ephantus Nyaga
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The rapid growth in technology has led to a very high demand for renewable sources of
energy which can be accessed by everyone irrespective of one's locality. CdS has so far
proved to be a good window material when matched with CU2Sas an absorber material of
the P-N junction for solar cell application. This research entails the doping of the
Cadmium sulphide with selenium so as to enhance optoelectric properties. Cd-Set.sS films
will be deposited using the CBD method. Chemicals to be used for this are; solutions of
pure ammonium nitrate, thiourea, sodium selenosulphate and cadmium nitrate. Solutions
of 0.004M cadmium nitrate, 0.008M ammonium nitrate, and 0.008M thiuorea in deionised
water will be prepared, stirred till all the particles are dissolved and 20m1of each
solution will be taken into a separate beaker. Doping of the CdxSel-xS films will be done
by varying volumes of uniform concentration of sodium selenosulphate (Na2SeS03)
solutions by volume at a constant deposition temperature of 80°c. The best value of x
realised will be maintained as the deposition temperature is varied from 60°c to 90°c.
Deposition of CU2Sfilm on a glass substrate will require the following Chemicals; copper
sulphate, hydrochloric acid, thiourea, and tartaric acid solutions of analytical grade. At a
constant temperature of 80°C, deposition of CU2Sfilms will be done as follows; 25mL of
copper sulphate will be complexed with 25ml of O.2M tartaric acid in a beaker, and then
25ml of 0.2M thiourea will be mixed in it with constant stirring. The pH will be adjusted
to 3 by addition of dilute hydrochloric acid with constant stirring using the pH meter. The
cleaned glass substrate will be immersed vertically into a beaker and the deposition
process will be carried out at different solution concentrations of CUS04 in order to
determine the optimum conditions for the deposition of Cu2S thin films. The best
concentration of CuS04 will be maintained as the deposition temperature is varied from
60°c to 90°c. The optical analysis of the thin films deposited above will be done using UVVIS
NIR 3700 spectrometer while the sheet resistivity will be done using the four point
probe method. Optical properties like reflectance and transmittance measured using UVVIS
NIR 3700 spectrophotometer will be used to calculate others optical properties like
band gap (Eg), refractive index (n), extinction coefficient (k) and absorbance (a). The
results will be analysed to determine how optical conductance, transmittance, absorbance
and the electrical resistivity varies with the conditions of deposition using the Scout
software. Finally the optimal values of CdxSel-xS and CU2S will be used to fabricate
(CdxSel_XS/CU2S)P-N junction for solar cell application. The solar cell P-N junction will
be characterized using the solar celJ simulator to find it's I-V characteristics and
parameters like fill factor (FF), conversion efficiency (11), and open circuit voltage (V00)'