Plechinger, Gerd and Schrettenbrunner, Franz-Xaver and Eroms, Jonathan and Weiss, Dieter and Schueller, Christian and Korn, Tobias (2012) Low-temperature photoluminescence of oxide-covered single-layer MoS2. Phys. Status Solidi RRL 6 (3), pp. 126-128.
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We present a photoluminescence study of single-layer MoS2 flakes on SiO2 surfaces. We demonstrate that the luminescence peak position of flakes prepared from natural MoS2, which varies by up to 25 meV between individual flakes, can be homogenized by annealing in vacuum. We use HfO2 and Al2O3 layers prepared by atomic layer deposition to cover some of our flakes. In these flakes, we observe a suppression of the low-energy luminescence peak which appears in asprepared flakes at low temperatures. We infer that this peak originates from excitons bound to surface adsorbates. We also observe different temperature-induced shifts of the luminescence peaks for the oxide-covered flakes. This effect stems from the different thermal expansion coefficients of the oxide layers and the MoS2 flakes. It indicates that the single-layer MoS2 flakes strongly adhere to the oxide layers and are therefore strained.
|Date:||2 January 2012|
|Institutions:|| Physics > Institute of Experimental and Applied Physics > Chair Professor Lupton > Group Christian Schüller|
Physics > Institute of Experimental and Applied Physics > Chair Professor Weiss > Group Dieter Weiss
|Projects:||SFB 689: Spinphänomene in reduzierten Dimensionen, GRK 1570, Elektronische Eigenschaften von Nanostrukturen auf Kohlenstoff-Basis|
|Keywords:||MoS2; two-dimensional crystals; photoluminescence|
|Subjects:||500 Science > 530 Physics|
|Refereed:||Yes, this version has been refereed|
|Created at the University of Regensburg:||Yes|
|Deposited On:||22 May 2012 13:10|
|Last Modified:||22 May 2012 13:10|