کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1450382 | 988732 | 2006 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Quantum dot-like behavior of ultrathin PbI2 films
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Vacuum-evaporated stoichiometric ultrathin discontinuous PbI2 films (in the range 2.5-30Â nm) show a linear grain size (4-16Â nm) growth with film thickness as revealed by transmission electron microscopy/X-ray diffraction analyses. A single peak around 3Â eV in the optical absorption spectra shows a systematic blue shift with decreasing grain size (d). The optical spectra show additional peaks for films thicker than 20Â nm. The 3Â eV peak has a linear dependence on 1/d2 indicating a typical quantum dot-like behavior yielding a corresponding bulk value of the transition as 2.98Â eV and the reduced effective mass of the electron-hole pair involved as 0.14. Relevant data from similar earlier studies agree quite well with our analysis. This study shows that an appropriate choice of the bulk optical transition concerned (not merely the minimum energy gap) is necessary for correctly interpreting the grain size-induced blue shift of optical structures for anisotropic and complex band structure materials like PbI2.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Acta Materialia - Volume 54, Issue 15, September 2006, Pages 3899-3905
Journal: Acta Materialia - Volume 54, Issue 15, September 2006, Pages 3899-3905
نویسندگان
Vikash Gulia, A.G. Vedeshwar, N.C. Mehra,