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.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12613598/index.pdf |
| Date | 01 September 2011 |
| Creators | Karaman, Mehmet |
| Contributors | Turan, Rasit |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for METU campus |
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