colloidal quantum dots offer broad tuning of semiconductor band structure via the quantum size effect. in this paper, we present a detailed investigation on the influence of the thickness of colloidal lead sulfide (pbs) nanocrystals (active layer) to the photovoltaic performance of colloidal quantum dot solar cells. the pbs nanocrystals (qds) were synthesized in a non-coordinating solvent, 1-oc...

We investigate exciton states theoretically in strained GaN/AlN quantum dots with wurtzite ~WZ! and zinc-blende ~ZB! crystal structures, as well as strained WZ GaN/AlGaN quantum dots. We show that the strain field significantly modifies the conductionand valence-band edges of GaN quantum dots. The piezoelectric field is found to govern excitonic properties of WZ GaN/AlN quantum dots, while it h...

objective(s): a large ratio of surface to volume of nanoparticles in comparison with bulk ones, will increase the cell penetration and therefore their toxicity. materials and methods: chemical precipitation method was used in order to synthesis of zns:ag quantum dots. their physical properties and characteristics were assessed by x-ray diffraction, ultra violet-visible spectrophotometer, transm...

We have investigated exciton states in wurtzite GaN/AlN and ZnO quantum dots. A strong piezoelectric field in GaN/AlN quantum dots is found to tilt conduction and valence bands, thus pushing the electron to the top and the hole to the bottom of the GaN/AlN quantum dot. As a result, the exciton ground state energy in GaN/AlN quantum dots with heights larger than 3 nm exhibits a red shift with re...

A noninteracting quantum-dot arrays side coupled to a quantum wire is studied. Transport through the quantum wire is investigated by using a noninteracting Anderson tunneling Hamiltonian. The conductance at zero temperature develops an oscillating band with resonances and antiresonances due to constructive and destructive interference in the ballistic channel, respectively. Moreover, we have fo...

...................................................................................................................... iii CHAPTER 1: BACKGROUND OF QUANTUM DOTS...................................................1 1.1 What Are Quantum Dots ................................................................................1 1.2 Fluorescence and Fluorescence Sensing......................................

Efforts are made in this thesis to reveal the dynamics of single-electron tunneling and to realize quantum bits (qubits) in semiconductor quantum dots. At low temperatures, confined single quantum dots and double quantum dots are realized in the twodimensional electron gas (2DEG) of AlGaAs/GaAs heterostructures. For transport studies, quantum dots are coupled to the drain and source contacts vi...

chemical precipitation method was used in order to synthesize cdse:ag quantum dots (2-3 nm). their physical properties and characteristics were assessed by x-ray diffraction, ultra violet-visible spectrophotometer and tem (transmission electron microscope) and it was shown that the obtained cdse:ag quantum dots are cubic with high-quality. antibacterial effects of cdse:ag nanoparticles against ...

glucose, as the major energy source in cellular metabolism, plays an important role in the natural growth of cells. herein, a simple, rapid and low-cost method for the glucose determination by utilizing glucose oxidase and cdte/thioglycolic acid (tga) quantum dots (qds) on a thin layer chromatography (tlc) plate has been described. the detection was based on the combination of the glucose enzym...

We provide a microscopic theory for semiconductor quantum dots that explains the pronounced deviations from the prevalent point-dipole description that were recently observed in spectroscopic experiments on quantum dots in photonic nanostructures. The deviations originate from structural inhomogeneities generating a large circular quantum current density that flows inside the quantum dot over m...