کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1814255 1025646 2008 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Thickness dependence of structural, electrical and optical behaviour of undoped ZnO thin films
موضوعات مرتبط
مهندسی و علوم پایه فیزیک و نجوم فیزیک ماده چگال
پیش نمایش صفحه اول مقاله
Thickness dependence of structural, electrical and optical behaviour of undoped ZnO thin films
چکیده انگلیسی

Undoped ZnO thin films of different thicknesses were prepared by r.f. sputtering in order to study the thickness effect upon their structural, morphological, electrical and optical properties. The results suggest that the film thickness seems to have no clear effect upon the orientation of the grains growth. Indeed, the analysis with X-ray diffraction show that the grains were always oriented according to the c(0 0 2)-axis perpendicular to substrate surface whatever the thickness is. However, the grain size was influenced enough by this parameter. An increase in the grain size versus the thickness was noted. For the electrical properties, measurements revealed behaviour very dependent upon thickness. The resistivity decreased from 25 to 1.5×10−3 Ω cm and the mobility increased from 2 to 37 cm2 V−1 s−1 when the thickness increased from 70 to 1800 nm while the carrier concentration seems to be less affected by the film thickness and varied slightly remaining around 1020 cm−3. Nevertheless, a tendency to a decrease was noticed. This behaviour in electrical properties was explained by the crystallinity and the grain size evolution. The optical measurements showed that all the samples have a strong transmission higher than 80% in the visible range. A slight shift of the absorption edge towards the large wavelengths was observed as the thickness increased. This result shows that the band gap is slightly decreases from 3.37 to 3.32 eV with the film thickness vary from 0.32 to 0.88 μm.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Physica B: Condensed Matter - Volume 403, Issue 18, 1 September 2008, Pages 3326–3330
نویسندگان
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