Crystallization dynamics of Ge in In/Ge bilayer films under swift heavy ion irradiation: Experimental and density functional theory studies
Abstract
Indium (In) metal induced crystallization (MIC) of a-Ge in In/poorly crystalline-Ge bilayer thin films under 120 MeV Ni7+ swift heavy ion (SHI) irradiation at different fluences of 1 × 1011, 5 × 1011, 1 × 1012, 5 × 1012 ions cm−2, followed by thermal annealing at 200 °C, is presented. The ion irradiation followed by thermal annealing leads to crystallization of a-Ge. The crystallization of a-Ge is decreasing with increasing ion fluence. Furthermore, it changes the lattice plane of In (101) to In (110), but that of Ge (111) remains the same. The interface mixing due to the ion irradiation is confirmed and explained using the thermal spike model. A new approach to explain the mechanism of MIC, density functional theory, is employed. The electronic and thermodynamic properties of the pristine and post-thermal annealed samples are compared. The interaction between the 4p orbital of Ge and the 5p orbital of In leads to the weakening of Ge–Ge bonds, which produces many free Ge atoms. The change in enthalpy is redistributed to lower entropy and a higher change in Gibbs free energy, which is responsible for the crystallization of a-Ge at a relatively lower temperature of 200 °C.
Article Details
Journal Info
Journal of Applied Physics
American Institute of Physics
Authors (15)
Topeswar Meher
Department of Pure and Applied Physics, Guru Ghasidas Vishwavidyalaya (A Central University) 1 , Bilaspur 495009,
Anshu Dewangan
Department of Pure and Applied Physics, Guru Ghasidas Vishwavidyalaya (A Central University) 1 , Bilaspur 495009,
Bharti Chandrakar
Department of Pure and Applied Physics, Guru Ghasidas Vishwavidyalaya (A Central University) 1 , Bilaspur 495009,
Sonali Patajoshi
Department of Physics, School of Natural Sciences, Shiv Nadar Institution of Eminence 2 , Gautam Buddha Nagar, Uttar Pradesh 201314,
Ambuj Mishra
Inter University Accelerator Centre 3 , Aruna Asaf Ali Marg, New Delhi 110067,
Sanjay Kumar Kedia
Inter University Accelerator Centre 3 , Aruna Asaf Ali Marg, New Delhi 110067,
S. Aggrawal
Ion Beam Centre, Department of Physics, Kurukshetra University 4 , Kurukshetra, Haryana 136119,
G. Singh
Dhirendra K. Chaudhary
Centre for Renewable Energy, Prof. Rajendra Singh Institute of Physical Sciences for Study and Research, V. B. S. Purvanchal University 5 , Jaunpur 222003,
Vineet K. Singh
Department of Physics, Deen Dayal Upadhyaya Gorakhpur University 6 , Gorakhpur 273009,
Udai B. Singh
Department of Physics, DDU Gorakhpur University 1 , Gorakhpur 273009,
S. Ojha
Inter University Accelerator Centre 3 , Aruna Asaf Ali Marg, New Delhi 110067,
F. Singh
Inter University Accelerator Centre 3 , Aruna Asaf Ali Marg, New Delhi 110067,
Aloke Kanjilal
Department of Physics, School of Natural Sciences, Shiv Nadar Institution of Eminence 2 , Gautam Buddha Nagar, Uttar Pradesh 201314,
Shiv P. Patel
Department of Pure and Applied Physics, Guru Ghasidas Vishwavidyalaya (A Central University) 1 , Bilaspur 495009,