Berlin 2018 – scientific programme
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O: Fachverband Oberflächenphysik
O 58: 2D materials beyond graphene: TMDCs, silicene and relatives II
O 58.2: Talk
Wednesday, March 14, 2018, 10:45–11:00, MA 043
On the adatom doping of 2-Dimensional siligene (SiGe) with alkali metals — •Amretashis Sengupta — BCCMS, University of Bremen, Am Fallturm 1, 28359 Bremen, Germany — Indian Institute of Engineering Science and Technology, Shibpur, Howrah - 711 103, India
An interesting hybrid 2D material, siligene has received attention for its possible applications in nanoelectronics and thermoelectrics. In this work we study the effect of adatom doping of 2D SiGe with alkali metal atoms (Li, Na and K), with density functional theory (DFT) simulations using generalized gradient approximation (GGA) and Perdew-Burke-Ernzerhof(PBE) functionals. The simulations showed a moderate adsorption energy of 0.75, 0.62 and 0.87eV for Li, Na and K atoms respectively, with possible doping concentrations upto M0.88SiGe (M=Li,Na,K). For ion-battery applications, the specfic capacites are evaluated as 223, 196 and 175 mAhg−1 for Li,Na and K storage respectively. Nudged elastic band (NEB) simulations showed a diffusion barrier of 0.71, 0.49 and 0.32eV for Li, Na and K atoms. In all cases a significant modulation in the Fermi energy (Ef) could be seen for varying degrees of doping. While Li adatom can dope the system from slight p-type to n-type (δEf=-0.05 to +0.5), the Na and K atoms dope the system from moderate to strongly n-type (δEf=+0.3 to +1.4 for Na and +0.6 to +1.86 for K) depending upon coverage. The results show possibilities concerning applications of 2D SiGe in ion-batteries, sensors and nanoscale devices.