Potential well

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

Electron Energy Levels in a Quantum Well within an In-Plane Magnetic Field

Abstract: The exact eigenenergy spectrum of an electron is calculated in a quantum well within an in‐plane magnetic field. The numerical solutions for the excited energy states as well as the ground‐state energy are found for various quantum‐well widths and barrier heights. The cyclotron orbits are considerably affected by the quantum well. The energy levels higher than the potential height of the quantum well and the energy levels lower than the potential height of the quantum well show quite different behaviors. These are explained with the properties of the combined potential and the wave function inherent to the system.

Variational calculation for the direct-gap exciton in the Ge quantum well systems

Abstract: The variational method based on the two-dimensional (2D), three-dimensional (3D), and anisotropic 3D exciton models is used to investigate the ground-level direct-gap electron-heavy-hole exciton behaviors in the Ge quantum well systems, including an infinite Ge well case and a Ge/SiGe finite well case. The exciton radius, binding energy, and oscillator strength are calculated for various well thicknesses and bias voltages. The three exciton models are compared indicating that the dimensionality in the exciton model is nearly 2D for the thin finite well and 3D with anisotropic exciton radiuses for the infinite well and thick finite well. The exciton radius minimum and oscillator strength maximum occur at 1.6 nm well for the finite well case, thus proving that this Ge/SiGe quantum well system possesses strong quantum confinement, even with a thin-well thickness. Also, the effect of the conduction-band nonparabolicity effect on the exciton behavior is discussed. The variational calculation agrees well with the experimental results and other theoretical calculations in the 10 nm finite well case.

Synthesis and optical properties of InP quantum dot/nanowire heterostructures

Abstract: Nanoscale heterostructures with modulated composition and/or passivated interfaces can enrich/enhance the performance of diverse compact devices. Here, we report the synthesis of nanoscale pearl-like InP nanowire heterostructures wrapped with InP quantum dots (QDs)-decorated PxOy nanospheres periodically along the length by a chemical vapor deposition (CVD) method. Compared with the Raman modes of bulk InP, additional surface phonon (SP) peak, which results from InP QDs finite size, is observed in these pearl-like heterostructures. Room-temperature photoluminescence (PL) showed that these pearl-like heterostructures simultaneously exhibited two broad emission bands at 768 and 846 nm, which belong to the PL emission of InP QDs and InP trunks, respectively. The significant blue shift of the two emission bands compared with the intrinsic luminescence of InP crystal at 920 nm is attributed to the quantum confinement effects. A self-organization model is proposed to illustrate the formation of the heterostructures. These interesting pearl-like InP/PxOy heterostructures may find potential applications in constructing new nanoscale optoelectronic devices.

A theoretical perspective of the enhanced photocatalytic properties achieved by forming tetragonal ZnS/ZnSe hetero-bilayer

Abstract: An efficient and economical way to tune the properties of two-dimensional (2D) materials is by forming van der Waals (vdW) hetero-layered structures in order to achieve a better performance in energy-related applications. In this theoretical work, we employ first-principles calculations to investigate a novel tetragonal (t-)ZnS/ZnSe hetero-bilayer (BL), as well as bilayers of ZnS and ZnSe only. A significant quantum confinement effect has been observed for all bilayers by state-of-the-art computations based upon the quasiparticle G0W0 approach and the Bethe–Salpeter equation (BSE). Among them, both t-ZnSe and t-ZnS/ZnSe BLs have strong optical absorption in the solar spectrum, rendering them potentially good candidates for solar energy harvesting. Moreover, the t-ZnS/ZnSe BL demonstrates good electron–hole separation by allocation of photo-induced electrons and holes in different layers, making it potentially suitable for applications in photocatalytic systems.