Characterization and fabrication of silicon thin films for solar cell applications

Download
2011
Karaman, Mehmet
In this thesis study, fabrication and characterization of silicon thin films prepared by magnetron sputtering and electron beam evaporation for solar cell applications have been investigated. In the first part of the study, magnetron sputtering method was used to fabricate thin hydrogenated amorphous silicon (a-Si:H) film on a Si substrate. Some samples were prepared on glass substrate for the basic characterizations like transmission and resistivity. Dark and illuminated I-V characteristics of the silicon heterojunction (SHJ) solar cells were studied as a function of material type and process parameters. It was observed that devices show diode characteristics, however their response to the illumination was quite weak. Low performance of the devices was discussed in terms of the resistivity and dopability of the sputtered film. The second part of the thesis deals with the fabrication and characterization of thin polysilicon films fabricated by e-beam evaporation. In order to dope the deposited Si films, a very thin boron film v was deposited by e-beam evaporation on SiO2 surface thermally grown on a Si wafer. Then an a-Si was evaporated by the same technique. Samples were annealed for polysilicon formation by using the technique called solid phase crystallization (SPC). The annealing was performed in two steps. The first step was the nucleation part, carried out at 475°C for 8 hours and the second step was the diffusion and crystallization parts that are accomplished at 900°C for several minutes. The Raman measurements revealed out the crystallinity and grain size. The crystallinity of the polysilicon thin films was also identified by X-Ray diffraction measurements. Finally, the Secondary Ion Mass Spectroscopy (SIMS) analysis was carried out to find out the amount of boron that diffuses into Si film. It was found that a graded boron profile, which is desirable for the solar cell applications, was achieved.

Suggestions

Investigation of solidification and crystallization of iron based bulk amorphous alloys
Erdiller, Emrah Salim; Akdeniz, Mahmut Vedat; Department of Metallurgical and Materials Engineering (2004)
The aim of this study is to form a theoretical model for simulation of glass forming ability of Fe ? Based bulk amorphous alloys, to synthesize Fe ? based multicomponent glassy alloys by using the predictions of the theoretical study, and to analyze the influence of crystallization and solidification kinetics on the microstructural features of this amorphous alloys. For this purpose, first, glass forming ability of Fe ? (Mo, B, Cr, Nb, C) ? X ( X = various alloying elements, selected from the periodic table...
Polysilicon thin film processing on glass and photovoltaic applications
Karaman, Mehmet; Turan, Raşit; Tüzün Özmen, Özge; Department of Micro and Nanotechnology (2016)
In this PhD study, crystallization of amorphous silicon on glass and its photovoltaic applications have been investigated. The crystallization of amorphous silicon (a-Si) was studied in two parts; Metal Induced Crystallization (MIC) and Laser Induced Crystallization (LIC). MIC method was first implemented by gold nanoparticle (AuNP) fabricated by dewetting technique by which gold thin films deposited on aluminium doped zinc oxide (AZO) coated glass were annealed for nanoparticle formation. A-Si was then depo...
Fabrication and doping of thin crystalline Si films prepared by e-beam evaporation on glass substrate
Sedani, Salar Habibpur; Turan, Raşit; Ünalan, Hüsnü Emrah; Department of Micro and Nanotechnology (2013)
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 h...
Light trapping by micro and nano-hole texturing of single-crystalline silicon solar cells
ALTINOLUK, Serra H.; CIFTPINAR, Hande E.; DEMİRCİOĞLU, Olgu; ES, FIRAT; BAYTEMİR, Gulsen; AKAR, Orhan; AYDEMİR, Akin; SARAC, Adem; Akın, Tayfun; Turan, Raşit (Elsevier BV; 2016-03-09)
The efficiency of a solar cell strongly depends on the interaction between the incoming light beam and the surface of the device. Any process enhances light-surface interaction increases absorption probability of the light; thus, improves generated current, in turn. Generated current could be improved either by light trapping or by increased device thickness. Considering fabrication costs and recombination losses, mechanically thin optically thick wafers are being focused on in terms of light trapping prope...
Design of high-efficiency dye-sensitized nanocrystalline solar cells
Yavuz, Halil İbrahim; Özenbaş, Ahmet Macit; Erçelebi, Ayşe Çiğdem; Department of Metallurgical and Materials Engineering (2014)
Nanocrystalline dye sensitized solar cells (DSSC) technology continues to develop as a better alternative to the silicon based solar cells, which are commercialized. This study aims at finding low cost and highly efficient DSSC design and production methods via examination of effects of both photoanode structure and photon-electron generation mechanism on photoanode layers. This will contribute to the commercialization of DSSC technology. Photoanode structure is examined in four groups; transparent conducti...
Citation Formats
M. Karaman, “Characterization and fabrication of silicon thin films for solar cell applications,” M.S. - Master of Science, Middle East Technical University, 2011.