GROWTH OF CNT/A-SI IN PECVD REACTORS FOR SOLAR CELL APPLICATIONS

• Main Author: Eliyana, Ajeng
• Format: Dissertations
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/83418
• Institution: Institut Teknologi Bandung

Technological advances and ever-increasing population growth have resulted in a large demand for energy globally, thereby accelerating threats to human survival. In this era where the increasing need for clean energy is the main focus, solar photovoltaic (PV) or solar cell technology has emerged as a promising candidate to meet these demands and become an alternative environmentally friendly energy source that is expected to be able to replace conventional petroleum-based energy sources. and coal. Solar cells mark an important point in the evolution of renewable energy technology. With the continued development of research and innovation, the hope of having a cleaner, more efficient and affordable energy source is getting closer. Along with this, strong support is needed from various parties, including industry, government and research institutions, to accelerate the adoption and development of this technology. Currently, the application of Carbon Nanotubes (CNT) in solar cells is of interest to photovoltaic researchers, because of its unique characteristics, namely wide optical absorption, durability, low resistance and high charge carrier mobility. Apart from that, CNTs have very large electrical conductivity so they are easier to conduct electric current, therefore they have the potential to increase the efficiency of thin film solar cells. Quality improvement is also carried out through development and optimization in experiments. One of the developments in CNT growth that has been carried out is the growth of metal catalysts, because they play an important role in the process of forming CNT tubes. Nickel (Ni) material is used as a metal catalyst which is grown on SiO4 and Corning glass substrates using the vacuum thermal evaporation method. Meanwhile, the hot wire cell in plasma-very high frequency-plasma enhanced chemical vapor deposition (HWC in plasma-VHF-PECVD) technique, which is a new modification of the development of the PECVD technique, is used to grow CNT layers and fabricate amorphous silicon (a-Si) based solar cell devices with optimization. i-layer thickness. The resulting CNT layer was obtained through optimization of several parameters, then applied in a solar cell device based on pi-n type amorphous silicon, with a Corning glass/TCO/Ni/CNT/a-Si (p-i-n) layer structure. Optimization in the growth of the Ni metal catalyst was obtained at a deposition time parameter of 50 s, with an annealing suhue of 500 ?C for 4.5 hours which produced a metal catalyst measuring 26.18 nm, with a standard deviation and polydispersity of 6.005 nm and 22.94 % respectively. Furthermore, the resulting Ni metal catalyst becomes a medium for the deposition of CNTs grown on a Corning glass+TCO substrate using the HWC in plasma-VHF-PECVD technique with optimization of deposition parameters including of CH4 precursor gas flow rate, deposition time, substrate suhue, and chamber pressure. From this optimization, CNT obtained with optimum results at a CH4 gas precursor flow rate of 80 sccm that deposited for 1 hour with a substrate suhue of 250 ?C and chamber pressure of 500 mTorr. Through this optimization, semiconducting CNTs were obtained with a diameter and length of ~29 nm and a length of ~2206 nm respectively, an ID/IG ratio of 0.87 with an energy band gap of 2.31 eV. The overall results obtained show that the energy band gap of the CNTs produced in this research includes a "wide band gap" so that CNTs can be well applied as a front layer in a-Si based p-i-n solar cell devices. The resulting CNT layer is then applied in amorphous silicon-based solar cells, which is one of the development options in this research by looking at the effect of the CNT layer on a-Si based p-i-n solar cell devices on optimizing the i-layer thickness. From the results of this application, the largest efficiency value of 0,061% was obtained at a i-layer thickness of 1.8 ?m. This research is the first research carried out at the PECVD KK FTMM ITB Laboratory, namely by applying a CNT layer to an a-Si based p-i-n solar cell device using the HWC in plasma-VHF-PECVD method. The process of deposition of the CNT layer on the a-Si solar cell device is carried out in-situ so that this research is more practical and economical. The results of this research can be an initial study in efforts that expected to provide new contributions in the development of solar cells, especially the application of CNT thin layers on a-Si solar cell devices.