TY - JOUR

T1 - Electronic properties and optical response of triangular and hexagonal MoS2 quantum dots. A DFT approach

AU - Bertel, R.

AU - Mora-Ramos, M. E.

AU - Correa, J. D.

N1 - Funding Information:
RB acknowledge financial support from the Universidad de la Guajira (Grant No 002-2017 , resolution 0512 of 2017). The authors thanks to Laboratorio de Simulación y Computación Científica of Universidad de Medellín for computational facilities. MEMR thanks the authorities and colleagues at the Universidad de Medellín for kind hospitality during the preparation of this work.

PY - 2019/5/1

Y1 - 2019/5/1

N2 - The energy states of triangular and hexagonal MoS2 quantum dots are studies with the use of density functional theory, varying the dot size. The system edges are assumed to be passivated with sulfur-hydrogen atoms. In each case, spin-up and spin-down polarizations are investigated via the calculation of the energy gaps, density of states and the interband optical response. The structures are found to be small gap semiconductors. In addition, from the calculated real and imaginary parts of the dielectric function the static index of refraction and the so-called energy loss are evaluated. The effect of the particular dot geometry on the physical quantities under study is specially discussed. It is found that the specific triangular configuration with a total of 42 atoms in the border exhibits a very small energy bandgap associated with the spin-up polarization, which leads to a significant deviation of the value of the related static index of refraction, compared with the remaining structures investigated. From the first-principles calculation it has been also possible to evaluate the spin-polarization and estimate the total magnetic moment, which ranges from ∼2μB to ~14μB, depending on the dot size and geometry.

AB - The energy states of triangular and hexagonal MoS2 quantum dots are studies with the use of density functional theory, varying the dot size. The system edges are assumed to be passivated with sulfur-hydrogen atoms. In each case, spin-up and spin-down polarizations are investigated via the calculation of the energy gaps, density of states and the interband optical response. The structures are found to be small gap semiconductors. In addition, from the calculated real and imaginary parts of the dielectric function the static index of refraction and the so-called energy loss are evaluated. The effect of the particular dot geometry on the physical quantities under study is specially discussed. It is found that the specific triangular configuration with a total of 42 atoms in the border exhibits a very small energy bandgap associated with the spin-up polarization, which leads to a significant deviation of the value of the related static index of refraction, compared with the remaining structures investigated. From the first-principles calculation it has been also possible to evaluate the spin-polarization and estimate the total magnetic moment, which ranges from ∼2μB to ~14μB, depending on the dot size and geometry.

KW - DFT

KW - MoS

KW - Optical

KW - Quantum-dot

UR - http://www.scopus.com/inward/record.url?scp=85060556382&partnerID=8YFLogxK

U2 - 10.1016/j.physe.2019.01.021

DO - 10.1016/j.physe.2019.01.021

M3 - Artículo

AN - SCOPUS:85060556382

VL - 109

SP - 201

EP - 208

JO - Physica E: Low-Dimensional Systems and Nanostructures

JF - Physica E: Low-Dimensional Systems and Nanostructures

SN - 1386-9477

ER -