Analysis of the effect of polarization traps and shallow impurities on the interlevel light absorption of quantum dots

Abstract

A spherical quantum dot (QD) heterosystem CdS/SiO 2 has been studied. Each QD has a hydrogen-like impurity in its center. Besides that, it has been accounted that a polarization trap for electron exists at the interfaces due to the difference between the QD and matrix dielectric permittivity. It has been defined that for small QD radii there are surface electron states. For different radii, partial contributions of the surface states into the electron energy caused by the electron-ion and electron-polarization charges interaction have been defined. The linear light absorption coefficient of noninteracting QDs has been calculated taking into account the QD dispersion by the size. It is shown that the surface states can be observed into different ranges of an electromagnetic spectrum.

Optical properties and single-electron states of the nanosystem that contains three quantum dots

“…The light absorption coefficient caused by the interlevel transition is determined on the basis of the formula [21,22]:…”

The Effect of Shallow Impurities on the Light Absorption by the Nanocrystals CdS

“…The solutions of Eq. (6) are expressed as the products of spherical functions and Coulomb or Whittaker functions [2][3][4]7], and the solutions of Eq. 7are the products of spherical functions and Bessel functions.…”

“…Therefore, the impurities may be in the QD and affect its properties. In this connection, there are a number of theoretical works [1][2][3][4][5][6][7][8][9], in which the energy spectra of donors and acceptors are determined as functions of the nanocrystal parameters.…”

Electron energy spectrum of the spherical GaAs/AlxGa1-xAs quantum dot with several impurities on the surface

“…Special attention is paid to hydrogenic impurities. There are many works regarding the hydrogenic impurities in the QD [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. Spherical [16, 17, 19-25, 27, 31, 32], cubic [33], parallelepipedshaped [26], lens-shaped [28], and ellipsoidal [18,29,30] QDs with impurities were studied.…”