Potential well

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

Quantum Well Infrared Photodetectors (QWIP)

Abstract: The idea of using multi-quantum well (MQW) structures to detect infrared radiation can be explained by using the basic principles of quantum mechanics. The quantum well is equivalent to the well known particle in a box problem in quantum mechanics, which can be solved by the time independent Schrodinger equation. Solutions to this problem involve the Eigen-values that describe the energy levels inside the quantum well in which the particle is allowed to exist. The position of the energy levels is primarily determined by the quantum well dimensions such as height and width. The chapter discusses quantum well infrared photodetectors (QWIP) that utilize the photo excitation of the electron (hole) between the ground state and the first excited state in the conduction band quantum well. The quantum well structure is designed so that these photo-excited carriers can escape from the quantum well and be collected as photocurrent. In addition to larger intersub-band oscillator strength, these detectors afford greater flexibility than extrinsically doped semiconductor infrared detectors because the wavelength of the peak response and cutoff can be continuously tailored by varying layer thickness and barrier composition.

Structural and Nonlinear Optical Properties of Self-Assembled SnO2-Doped Silicon Nanorings Formed by Pulsed Laser Ablation

Abstract: SnO 2 -doped Si nanorings with an outer diameter of 25 nm and an average width of 5 nm are grown by pulsed laser deposition. Atomic force microscopy reveals several interesting self-assembling forms of polycrystalline as well as an amorphous type of silicon nanorings. Depending on the width of the ring, the optical bandgap and photoluminescence can be tuned from the near infrared (1.38 eV) to the ultraviolet (3.02 eV), giving evidence for the strong quantum confinement effect along the width of ringlike quantum states. From Z-scan studies, the two-photon absorption coefficient is determined to be 2.2 X 10 -6 m/W.

Optical properties of armchair graphene nanoribbons with Stone–Wales defects and hydrogenation on the defects

Abstract: Armchair graphene nanoribbon (AGNR) is one of the most investigated semiconducting graphene materials. The controllable approach on AGNR is quite useful for future optical applications. To realize the aim, optical properties of three AGNRs with Stone–Wales (SW) defects and hydrogenation on the SW defects (SW-H) are theoretically investigated. W8, W9 and W10 AGNRs are chosen based on the width (W) index of n. SW defects enlarge the band gap of W8, and reduce the band gap of W9 and W10. The hydrogenations increase the band gaps of W8- and W9-SW, and decrease the one of W10-SW. The distributions of exciton wavefunctions located near one edge of W10-SW-H, revealed an obvious quantum confinement effect. In W10 serials, the exciton binding energy difference between SW and SW-H structures is only 0.08 eV, indicating tuneable optical applications with this small exciton binding energy switch. Due to the strong optical absorption and small exciton binding energy of W9-SW, it also possesses potential applications for luminescence and photovoltaic devices.