Potential well

About: Potential well is a research topic. Over the lifetime, 1430 publications have been published within this topic receiving 30812 citations.

Ag2ZnSnS4 Nanocrystals Expand the Availability of RoHS Compliant Colloidal Quantum Dots

Abstract: The demonstration of the quantum confinement effect in colloidal quantum dots (QDs) has been extensively studied and exploited mainly in Pb and Cd chalcogenide systems. There has been an urgent nee...

Visible-light driven photocatalytic hydrogen generation by water-soluble all-inorganic core–shell silicon quantum dots

Abstract: The photocatalytic hydrogen (H2) generation by boron (B) and phosphorus (P) codoped silicon quantum dots (Si QDs) with diameters in the quantum confinement regime is investigated. The codoped Si QDs have an amorphous shell made from B, Si and P. The shell induces negative potential on the surface and makes codoped Si QDs dispersible in water. The hydrophilic shell offers enhanced stability and efficiency in photocatalytic H2 generation and provides the opportunity to study the size dependence of the H2 generation rate. A drastic increase of H2 generation rate with decreasing QD size is observed. Analyses based on the Marcus theory reveal that the upper shift of the lowest unoccupied molecular orbital level of Si QDs by the quantum confinement effect is responsible for the enhanced photocatalytic activity.

Large g value in CuCl semiconductor microcrystallites

Abstract: A magnetic circular dichroism measurement is applied to semiconductor microcrystallites. The effective g values of CuCl semiconductor microcrystallites embedded in polymer matrix are found to be 0.447 and -0.18 for the Z 3 and Z 12 exciton states, respectively, the former being 1.49 times enhanced from the bulk value. The result is a direct consequence of the quantum confinement effect, explained in terms of the change in amplitudes of the components with higher (index in the lowest exciton state

Transitions of bandgap and built-in stress for sputtered HfZnO thin films after thermal treatments

Abstract: HfZnO thin films with various Hf contents are sputter-deposited on glass substrates from HfxZn1−xO (x = 0, 2.5, 5, 7.5, and 10 at. %) targets at room temperature. The incorporation of Hf in the ZnO film leads to the amorphorization of the materials. The amorphous structures of high-Hf-content films remain after annealing at 600 °C for 30 min. The built-in stresses of as-deposited films are compressive. As the annealing temperature increases, the stresses are relaxed and even become tensile. The films exhibit a high transmission of 80% in the visible region. The optical bandgap increases with the Hf content, but it decreases with the annealing temperature. This can be attributed to the alteration of strain (stress) status in the films and atomic substitution. The reduction of bandgap partly results from the grain growth, which is due to the quantum confinement effect of the small grains. Hf doping increases the resistivity of ZnO owing to the disorder of the material structure and the higher bandgap, which...

Exciton states in quasi-zero-dimensional semiconductor nanosystems

Abstract: The variational method in the context of the modified effective mass approximation is used to calculate the dependence of exciton ground-state energy for a quantum dot embedded in a borosilicate glassy matrix on the quantum dot radius. It is shown that the peaks in the absorption and low-temperature luminescence spectra of such a nanosystem are shifted to shorter wavelengths due to size quantization of the exciton ground-state energy in the quantum dot.