CdSe thin films were deposited by thermal evaporation and e-beam
evaporation techniques on to well cleaned glass substrates. Low dose of boron have
been implanted on a group of samples. EDAX and X-ray patterns revealed that
almost stoichiometric polycrystalline films have been deposited in (002) preferred
orientation. An analysis of optical measurements revealed a sharp increase in
absorption coefficient below 700 nm and existence of a direct allowed transition. The
calculated band gap was around 1.7 eV. The room temperature conductivity values
of the samples were found to be between 9.4 and 7.5x10-4 (& / #937 / -cm)-1 and 1.6x10-6 and
5.7x10-7 (& / #937 / -cm)-1for the thermally evaporated and e-beam evaporated samples
respectively. After B implantation conductivity of these films increased 5 and 8
times respectively. Hall mobility measurements could be performed only on the
thermally evaporated and B-implanted e-beam evaporated samples and found to be
between 8.8 and 86.8 (cm2/V.s). The dominant conduction mechanism were
determined to be thermionic emission above 250 K for all samples. Tunneling and
v
variable range hopping mechanisms have been observed between 150-240 K and 80-
140 K respectively. Photoconductivity & / #8211 / illumination intensity plots indicated two
recombination centers dominating at the low and high regions of studied temperature
range of 80-400 K. Photoresponse measurements have corrected optical band gap
measurements by giving peak value at 1.72 eV.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12607608/index.pdf |
| Date | 01 September 2006 |
| Creators | Hus, Saban Mustafa |
| Contributors | Parlak, Mehmet Prof. Dr. |
| 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 public access |
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