Adição de partículas em pontos quânticos de fosforeno

Abstract

In this work, we calculate the additional energy spectra of phosphorene quantum dotsunder realistic conditions, focusing on the role of quantum dot size, edge passivation,number of layers, and substrate dielectric constant where the dots are deposited. Inour theoretical model we obtain single-particle states using the tight-binding method.These states are used to construct the Slater determinants,representing the total wavefunction of the N-electron system. The total energy of the system is calculated accordingto the Hartee-Fock theory. We consistently obtained additional energies higher than thethermal energykBT. This suggests that Coulomb blockade at room temperature can beobserved in phosphorene quantum dots, depending on trade-off between quantum dot size,dielectric constante of the substrate, and passivation state of the quantum dots edges: thelarger the size of the quantum dot, the smaller is the dielectric constant of the substratethat allows for Coulomb blockade at room temperature. On theother hand, observingCoulomb blockade in smaller dots depends on the passivationstate of the edges. If theedges are fully passivated, Coulomb blockade is observed for any substrate with up toǫsub= 30. If the edges are unpassivated, Coulomb blockade can only be observed for uptoepsilonsub= 15. This dramatic role of the substrate is expected to impactnot only thedevelopment of charge storage applications of phosphorene quantum dots, but also opticalapplications, where dielectric screening effects plays a major role. Finally, we emphasizethat the advantage of our methodology goes beyond simplicity of implementation. Itallows us to predict accurate values of phosphorene quantum dot charge energies.