Impact of shell thickness on exciton and biexciton binding energies of a ZnSe/ZnS core–shell quantum dot

Effect of Shell Thickness on Electron and Hole Transmission Probabilities of a ZnSe/ZnS Core- Shell Quantum Dot

“…The material parameters used for numerical calculations are: 0 is the effective mass of electron, effective mass of hole and rest mass of the charge respectively 12-14 . Our theoretical model is similar to Sen et al 10 , therefore in our calculations we used two different core radii 1.25nm and 2.25nm with varying shell thickness from 0 to 5nm, besides valence band offset V v =0.58eV for core radius of 1.25nm, valence band offset V v =0.14eV for core radius of 2.25nm, conduction band offset V v =0.1eV for core radius of 1.25nm and conduction band offset V v =0.03eV for core radius of 2.25nm.…”

“…So by over coating the ZnSe core by higher band gap ZnS shell results in an enhancement in localization of the charge carriers which has a wide application in calculating spin polarized current in quantum dots. The extra deposited ZnS shell thickness strongly controls the function of the electron transfer in quantum dots, bio-sensor or chemo-sensorand the inclusion of tunneling property is of utmost importance to study the effect of shell thickness on the tunneling probabilities and energy level structures of the CSQDs 9 .Moreover, the presence of shell results increase in exciton and biexciton energies and red shift in PL spectra in the CSQDs 10 . In the present work the barrier penetration (tunneling) probabilities have been theoretically calculated for ZnSe/ZnS core-shell quantum dots under strained configuration using varying potential barrier which depends on the conduction band offset of the QD.…”

A Tunneling Dielectric Layer Free Floating Gate Nonvolatile Memory Employing Type‐I Core–Shell Quantum Dots as Discrete Charge‐Trapping/Tunneling Centers

“…The average diameters of ZnSe‐OA and ZnSe@ZnS‐OA QDs are estimated to be 4.2 ± 0.4 nm and 5.2 ± 0.4 nm, respectively. The thickness of 1 nm is consistent with the synthesis parameter of three monolayers of ZnS . The insets in Figure a,b are the high‐resolution TEM (HRTEM) images for each kind of QD.…”

“…Besides, considering the optoelectronic versatility of semiconductors compared with metals, it is worth investigating the application of semiconductor nanoparticles with the same charge confinement ability as the metal‐dielectric structure (e.g., type‐I core–shell quantum dots) in the FGT. In the present work, we demonstrate that the type‐I ZnSe/ZnS core–shell quantum dots, which do not contain toxic or noble element, can operate well as the discrete charge‐trapping/tunneling centers in an FGT nonvolatile memory. This FGT nonvolatile memory based on ZnSe/ZnS core–shell quantum dots showed a large memory window, a good endurance, and a stable retention.…”

Optical properties of type-I PbSe/CdSe core/shell quantum dot

“…Enhancement of groundstate exciton energy with the reduction of shell radius is observed. The exciton binding energy is found to be more for smaller shell radius whereas it is less for larger shell radius [26]. Moreover, for thin core/shell materials, the leakage of exciton wave function occurs and consequently it penetrates into the core material.…”