کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5363187 | 1388298 | 2008 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Strong inter-conduction-band absorption in heavily fluorine doped tin oxide
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله

چکیده انگلیسی
The optical, electrical and structural properties of thin film tin oxide (TO), F-doped tin oxide (FTO; nF â 6 Ã 1020 cmâ3) and highly F-doped tin oxide (hFTO; nF â 10 Ã 1020 cmâ3), grown by spray pyrolysis technique, are studied by atomic force microscopy, Hall effect, X-ray fluorescence and transmission/reflection measurements. The resistivity (Ï = 32 Ã 10â4 Ω cm for intrinsic tin oxide) shows intriguing characteristics when F concentration nF is increased (Ï = 6 Ã 10â4 Ω cm for FTO but 25 Ã 10â4 Ω cm for hFTO) whereas the carrier concentration is almost constant at high F concentration (nc â 6 Ã 1020 cmâ3 for FTO and hFTO). Thus, F seems to act both as a donor and a compensating acceptor in hFTO. The high carrier concentration has a strong effect on the optical band-edge absorption. Whereas intrinsic TO has room-temperature band-gap energy of Eg â 3.2 eV with an onset to absorption at about 3.8 eV, the highly doped FTO and hFTO samples show relatively strong absorption at 2-3 eV. Theoretical analysis based on density functional calculations of FTO reveals that this is not a defect state within the band-gap region, but instead a consequence of a hybridization of the F donor states with the host conduction band in combination with a band filling of the lowest conduction band by the free carriers. This allows photon-assisted inter-conduction band transitions of the free electrons to energetically higher and empty conduction bands, producing the below-gap absorption peak.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied Surface Science - Volume 255, Issue 5, Part 1, 30 December 2008, Pages 1874-1879
Journal: Applied Surface Science - Volume 255, Issue 5, Part 1, 30 December 2008, Pages 1874-1879
نویسندگان
Carla D. Canestraro, Marcela M. Oliveira, Rogério Valaski, Marcus V.S. da Silva, Denis G.F. David, Iuri Pepe, Antonio Ferreira da Silva, Lucimara S. Roman, Clas Persson,