کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7987844 | 1515528 | 2018 | 11 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
The study of dispersive 'b'-mode in monolayer MoS2 in temperature dependent resonant Raman scattering experiments
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موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
دانش مواد (عمومی)
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
We report on resonant Raman scattering studies of monolayer MoS2 as a function of the excitation laser energy (1.959-2.033â¯eV) and temperature (Tâ¯=â¯7-295â¯K). In complementary reflectivity contrast experiments we determined the temperature evolution of the A exciton and trion resonances. We focus our studies on the dispersive, second order 'b' mode related to the resonant two phonon Raman process of successive emissions of the acoustic LA and TA phonons at K points. We found that when excitation laser energy is tuned across the A exciton level this mode shifts almost linearly to lower frequency with the rate equal â83 and â71â¯cmâ1/eV at Tâ¯=â¯7 and 295â¯K, respectively, which is about two times higher rate than those reported in the previous studies of monolayer MoS2 but very close the relevant rate recorded for bulk MoS2. We interpret this effect as related to the difference of concentration of two dimensional electron gas. We also determined, using excitation with the He-Ne laser the temperature shifts of the Raman peaks of dispersive 'b' and dispersionless Eâ² and A1â² modes. We found that absolute value of the temperature coefficient of 'b' mode, equals 3.5â¯Ãâ¯10â2â¯cmâ1/K, is much higher than those of Eâ² and A1â² modes, equal 0.4â¯Ãâ¯10â2 and 0.8â¯Ãâ¯10â2â¯cmâ1/K, respectively.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Solid State Communications - Volume 275, July 2018, Pages 25-28
Journal: Solid State Communications - Volume 275, July 2018, Pages 25-28
نویسندگان
Joanna Kutrowska-Girzycka, Joanna Jadczak, Leszek Bryja,