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...

In this paper, using the tight-binding model, we extend the real-space renormalization group method to time-dependent Hamiltonians. We drive the time-dependent recursion relations for the renormalized tight-binding Hamiltonian by decimating selective sites of lattice iteratively. The formalism is then used for the calculation of the local density of electronic states for a one dimensional quant...

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...

...................................................................................................................... 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...

Nanopartmles have been used as an approach to improve the pharmacodynamic and phannacokinetie propertiesof various drues. Amino acids have been considered to be useful to make such nano particles because ofthocompatithe and biodegradable characteristic. The quantum mechanical method that was chosen to analyze inethio hexa peptide nano ring]. The structure of some peptide nanorrigs as well as th...

in this paper, we study the electronic properties of a concentric triple quantum ring using exact diagonalization technique. the energy spectra and magnetization for a single electron and two electrons, in the presence of an applied magnetic field, are calculated and discussed. it is shown that, for two-interacting electrons, the period of aharonov-bohm oscillations decreases to the half of tha...

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...