Fabrication and doping of thin crystalline Si films prepared by e-beam evaporation on glass substrate

Download

index.pdf

Date

2013

Author

Sedani, Salar Habibpur

Metadata

Show full item record

Item Usage Stats

491
views

176
downloads

In this thesis study, fabrication and doping of silicon thin films prepared by electron beam evaporation equipped with effusion cells for solar cell applications have been investigated. Thin film amorphous Si (a-Si) layers have been fabricated by the electron beam evaporator and simultaneously doped with boron (B) and phosphorous (P) using effusion cells. Samples were prepared on glass substrates for the future solar cell operations. Following the deposition of a-Si thin film, crystallization of the films has been carried out. Solid Phase Crystallization (SPC) and Metal Induced Crystallization (MIC) have been employed to obtain thin film crystalline Si. Crystallization was performed in a conventional tube furnaces and Rapid Thermal annealing systems (RTA) as a function of process parameters such as annealing temperature and duration. Produced films have been characterized using chemical and structural characterization techniques such as Raman Spectroscopy, X-Ray Diffractometer and Secondary Ion Mass Spectrometer (SIMS). The electrical properties of the films have been studied using Hall Effect and I-V measurements as a function of doping. We have demonstrated successful crystallization of a-Si by SPC at temperatures above 600 °C. The crystallization occurred at lower temperatures in the case of MIC. For doping, P was evaporated from the effusion cell at a temperature between 600 °C and 800 °C. For B, the evaporation temperature was 1700 °C and 1900 °C. The thickness and the band gap of the Si films were determined by ellipsometry method and the results were compared for different evaporation temperatures. The effect of doping was monitored by the I-V and Hall Effect measurements. We have seen that the doping was accomplished in most of the cases. For the samples annealed at relatively high temperatures, the measured doping type was inconsistent with the expected results. This was attributed to the contamination from the glass substrate. To understand the origin of this contamination, we analyzed the chemical structure of the film and glass by X-ray Fluorescence (XRF) and seen that the glass is the main source of contamination. In order to prevent this contamination we have suggested covering the glass substrate with Si3N4 (Silicon Nitride) which act as a good diffusion barrier for impurities.

Subject Keywords

Thin films., Silicon solar cells., Silicon nitride., Crystallization.

URI

http://etd.lib.metu.edu.tr/upload/12615628/index.pdf
https://hdl.handle.net/11511/22615

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Crystallization and phase separation mechanism of silicon oxide thin films fabricated via electron beam evaporation of silicon monoxide Gündüz, Deniz Cihan; Turan, Raşit; Yerci, Selçuk; Department of Micro and Nanotechnology (2015) Silicon nanocrystals (NCs) imbedded in a matrix of silicon oxide have drawn much attention due to their applications in optoelectronic devices and third-generation solar cells. Several methods were reported for the fabrication of Si NCs. Among these techniques, there are aerosol synthesis, chemical vapor deposition, ion implantation, magnetron sputtering and thermal evaporation. However, electron beam evaporation is a straightforward and effective technique for the fabrication of silicon oxide thin films si...
Development of hole transport transparent conductive electrodes for n-type crystalline silicon solar cells Akdemir, Ozan; Bek, Alpan; İmer, Muhsine Bilge; Department of Micro and Nanotechnology (2018) Conventional transparent conductive electrodes (TCEs) used in crystal silicon (c-Si) solar cells are commonly made of indium tin oxide (ITO) which provides low sheet resistance and high transparency. However, due to indium scarcity, ITO layers increase the fabrication cost; thus, alternative TCEs, such as fluorine-doped tin oxide (FTO), zinc oxide (ZnO), metal nanowires and Oxide/Metal/Oxide (OMO) multilayers, are being investigated. Conventional solar cells also make use of doped layers, to create the junc...
Growth and morphological characterization of intrinsic hydrogenated amorphous silicon thin film for a-Si:H/c-Si heterojunction solar cells Pehlivan, Özlem; Tomak, Mehmet; Kodolbaş, Alp Osman; Department of Physics (2013) Passivation of the crystalline silicon (c-Si) wafer surface and decreasing the number of interface defects are basic requirements for development of high efficiency a-Si:H/c-Si heterojunction solar cells. Surface passivation is generally achieved by development of detailed silicon wafer cleaning processes and the optimization of PECVD parameters for the deposition of intrinsic hydrogenated amorphous silicon layer. a-Si:H layers are grown in UHV-PECVD system. Solar cells were deposited on the p type Cz-silic...
Integration of graphene with GZO as TCO layer and its impact on solar cell performance Zan, Recep; Olgar, Mehmet Ali; Altuntepe, Ali; Seyhan, Ayse; Turan, Raşit (2022-01-01) In this study, we investigated the impact of incorporating graphene with Ga-doped ZnO (GZO) when employing them as a TCO layer on Si-based solar cell. GZO thin films with various thicknesses (50-450 nm) were fabricated by the sputtering method using a single target. The aim here was to determine the GZO film with the optimum thickness to incorporate it with single layer graphene as TCO. This thickness was found to be 350 nm as that was the best crystalline quality found in the Opattern. Further, this sample...
Fabrication of thin crystalline silicon solar cells with advanced light trapping Hadibrata, Wisnu; Yerci, Selçuk; Turan, Raşit; Department of Micro and Nanotechnology (2017) Thin crystalline silicon (c-Si) solar cells with thickness in the order of few tens of microns offer many attractive applications, such as, electronic wearables, space probes and satellites thanks to their flexibility and light-weight character. However, reducing the thickness of active layer of silicon solar cells leads to poor light absorption within the silicon layer, especially in the near infrared region of the solar spectrum. The poor absorption becomes problematic for thin c-Si solar cells as it caus...

Citation Formats

S. H. Sedani, “Fabrication and doping of thin crystalline Si films prepared by e-beam evaporation on glass substrate,” M.S. - Master of Science, Middle East Technical University, 2013.