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Theoretical studies of rolled-up and wrinkled nanomembranes
Čendula, Peter ; Holý, Václav (advisor) ; Fedorchenko, Alexander I. (referee) ; Onck, Patrick N. (referee)
Title: Theoretical studies of rolled-up and wrinkled nanomembranes Author: Mgr. Peter Cendula Department: Department of Condensed Matter Physics Thesis Supervisors: Prof. Dr. Oliver G. Schmidt, Prof. RNDr. Václav Holý, CSc. Abstract : The thesis is devoted to three similar topics from the field of rolled-up and wrinkled nanomembranes. We start by recalling classical theory of thin plates, which will be used to describe deformation of nanomembranes. In the first topic, relaxation of internal strain is studied when a flat film is partially released from the substrate by etching the sacrificial layer underneath. Energetic competition of the tube and wrinkle shape is quantitatively investigated. Similar model is used to investigate the limiting maximum value of tube rotations. In the second topic, roll-up of initially wrinkled film is shown to favor tubes forming on the flat edge of rectangular wrinkled pattern, enabling precise control of tube position. Experiment is provided to justify our theoretical predictions. In the third topic, quantum well is assumed inside a wrin- kled nanomembrane. Shift of transition energy induced by lateral modulation due to bending strain is quantified, being of interest for strain-sensitive optical detectors and emitters. In addition, lateral localization of electron and hole due to...
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Theoretical studies of rolled-up and wrinkled nanomembranes
Čendula, Peter ; Holý, Václav (advisor) ; Fedorchenko, Alexander I. (referee) ; Onck, Patrick N. (referee)
Title: Theoretical studies of rolled-up and wrinkled nanomembranes Author: Mgr. Peter Cendula Department: Department of Condensed Matter Physics Thesis Supervisors: Prof. Dr. Oliver G. Schmidt, Prof. RNDr. Václav Holý, CSc. Abstract : The thesis is devoted to three similar topics from the field of rolled-up and wrinkled nanomembranes. We start by recalling classical theory of thin plates, which will be used to describe deformation of nanomembranes. In the first topic, relaxation of internal strain is studied when a flat film is partially released from the substrate by etching the sacrificial layer underneath. Energetic competition of the tube and wrinkle shape is quantitatively investigated. Similar model is used to investigate the limiting maximum value of tube rotations. In the second topic, roll-up of initially wrinkled film is shown to favor tubes forming on the flat edge of rectangular wrinkled pattern, enabling precise control of tube position. Experiment is provided to justify our theoretical predictions. In the third topic, quantum well is assumed inside a wrin- kled nanomembrane. Shift of transition energy induced by lateral modulation due to bending strain is quantified, being of interest for strain-sensitive optical detectors and emitters. In addition, lateral localization of electron and hole due to...
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Strmé InAs/GaAs heteropřechody a velmi tenké kvantové jámy vypěstované pomocí MOVPE
Hulicius, Eduard ; Pacherová, Oliva ; Oswald, Jiří ; Hospodková, Alice ; Pangrác, Jiří ; Šimeček, Tomislav ; Melichar, Karel ; Petříček, Otto ; Chráska, T. ; Holý, V. ; Vávra, I. ; Ouattara, L.
We have found that the abruptness and symmetry on monoatomic scale is achievable with MOVPE technique as well. We are able to find only the periodicity in these structures while atomic resolution pictures give reliable thickness values.
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