Efficiency Study of PbTe/CdTe Core/Shell Quantum Dots Solar Cells

In this work we theoretically study how to optimize the efficiency of an intermediate band solar cell based on IV-VI PbTe/CdTe semiconductor materials. We focus our attention on how control structural parameters, such as the height and radius in cylindrical quantum dots and the radius in spherical quantum dots to obtain the inter and intraband transition energies that provide the highest efficiency values of the solar cell. The calculation of the energy levels, the selection rules for transitions energies were performed using the 4×4 k.p Kane-Dimmok Hamiltonian.

Exploring Noise-Effect on the Intraband Transition Lifetime of Impurity Doped Quantum Dots

Current inspection analyzes the role played by Gaussian white noise on intraband transition lifetime (ITL) of quantum dot (QD) containing an impurity. In this regard, the ITL profiles are scrutinized following the variation of several pertinent physical quantities with and without noise. Two different avenues viz. 'additive' and 'multiplicative' have been explored by which noise may be introduced to the system. Often, the presence of noise happens to alter the attributes of the ITL profiles (steady rise, steady fall, and maximization) from that under a noise-free state. And such alterations also prominently depend on the additive/multiplicative nature of noise. The present study clearly manifests the attainment of enhanced ITL of QDs containing dopants under applied Gaussian white additive noise having strength in the neighborhood of a typical value. The findings seem to have important bearings in designing and manufacturing QD-based optoelectronic devices where the role of noise needs to be acknowledged.

Reflection Enhancement and Giant Lateral Shift in Defective Photonic Crystals with Graphene

This study investigates the reflectance of the defective mode (DM) and the lateral shift of reflected beam in defective photonic crystals incorporated with single-layer graphene by the transfer matrix method (TMM). Graphene, treated as an equivalent dielectric with a thickness of 0.34 nm, was embedded in the center of a defect layer. The reflectance of the DM was greatly enhanced as the intraband transition of electrons was converted to an interband transition in graphene. The reflectance of the DM could be further enhanced by increasing the Bragg periodic number. Furthermore, a large lateral shift of the reflected beam could also be induced around the DM. This study may find great applications in highly sensitive sensors.