Özet:
Solar energy has regarded as the latest comparatively sustainable energy source
due to its low cost, eco-friendly and large scale the productibility. Silicon-based
solar cells having a significant interest for many years. However, production and
fabrication techniques are demanded which make the solar cells more cheaper.
Therefore, thin film solar cells have emerged to be an alternative. Thin film
technology is considered as inexpensive given that devices have a small amount
of material and are established on varied pattern of light absorbing
semiconductors. Furthermore, appropriate materials should be prepared,
inexpensive, and show a stable behavior over long periods of operation. Zinc
sulfide and zinc oxide are considered as the most favorable materials for
heterojunction solar cells.
This thesis aims to produce high efficiency and cost-effective solar cells by useing
the energy that comes from the sun as an alternative and clean energy source. ZnS
and ZnO thin films including silicon based solar cells were grown by using easy
and economic techniques which are chemical bath deposition, spin coating, and
spray pyrolysis techniques. Properties of undoped and Na doped ZnS thin films
were grown on glass and Si substrates by spray pyrolysis were investigated. Effect
of annealing time and precursor solution amount of ZnO films on the optical
properties were investigated. Structural, morphological, optical and electrical
properties were examined by using XRD, SEM, UV-Visible spectrometry, and
resistivity measurement.
It had been found that the band gap energy of ZnS film was decreased to 3.42 eV
from 3.66 eV and the resistivity of the film was decreased to 2.00 x105 Ω from
5.17 x105 Ω with increasing Na doping concentration. Performance of ZnS/Si
heterojunction cell was improved to increase from 2.20% to 5.06% by Na doping.
Moreover, the conversion efficiency of undoped and Na doped ZnS/Si is higher
than undoped ZnO/Si fabricated under the same condition.