Related papers: On quantitative analysis of interband recombinatio…
In this work we develop a simple theory for the green photoluminescence of ZnO quantum dots (QDs) that allows us to understand and rationalize several experimental findings on fundamental grounds. We calculate the spectrum of light emitted…
The determination of minority-carrier lifetimes and surface recombination velocities is essential for the development of semiconductor technologies such as solar cells. The recent development of two-photon time-resolved microscopy allows…
Two-photon time-resolved photoluminescence has been recently applied to various semiconductor devices to determine carrier lifetime and surface recombination velocities. So far the theoretical modeling activity has been mainly limited to…
Nanometer-thick quantum-well structures are quantum model systems offering a few discrete unoccupied energy states that can be impulsively filled and that relax back to equilibrium predominantly via spontaneous emission of light. Here we…
The increased complexity and reduced size of (opto-)electronic devices demands for quantitative descriptions of excess carrier transport and recombination via various mechanisms. In addition, experimental methods capable of resolving…
Investigations that probe defects one at a time offer a unique opportunity to observe properties and dynamics that are washed out of ensemble measurements. Here we present confocal fluorescence measurements of individual defects in Al-doped…
We generalize and systematize basic experimental data on optical and luminescence properties of ZnO single crystals, thin films, powders, ceramics, and nanocrystals. We consider and study mechanisms by which two main emission bands occur, a…
Doped ZnO is a promising material for spintronics applications. For such applications, it is important to understand the spin dynamics and particularly the spin coherence of this II-VI semiconductor. The spin lifetime $\tau_{s}$ has been…
We study the optical properties of thin flakes of InSe encapsulated in hBN. More specifically, we investigate the photoluminescence (PL) emission and its dependence on sample thickness and temperature. Through the analysis of the PL…
Electrons photoemitted by extreme ultraviolet attosecond pulses derive spatially from the first few atomic surface layers and energetically from the valence band and highest atomic orbitals. As a result, it is possible to probe the emission…
At carrier densities above the Mott density Coulomb screening destroys the exciton resonance. This, together with band-gap renormalization and band filling, severely affects the optical spectra. We have experimentally studied these effects…
The evolution of charge carriers in photoexcited room temperature ZnO nanoparticles in solution is investigated using ultrafast ultraviolet photoluminescence spectroscopy, ultrafast Zn K-edge absorption spectroscopy and ab-initio molecular…
Ultrafast time-resolved photoluminescence spectroscopy following one- and two-photon excitation of ZnO powder is used to gain unprecedented insight into the surprisingly high external quantum efficiency of its "green" defect emission band.…
Previous luminescence and absorption experiments in Co-doped ZnO revealed two ionization and one intrashell transition of $d(\textrm{Co}^{2+})$ electrons. Those optical properties are analyzed within the generalized gradient approximation…
Motivated by recent experiments on radiative recombination of two-dimensional electrons in acceptor doped GaAs-AlGaAs heterojunctions as well as the success of a harmonic solid model in describing tunneling between two-dimensional electron…
We investigate non-equilibrium electron dynamics in crystalline ZnO induced by ultrashort, relatively intense, infrared laser pulses. Our focus is on understanding the mechanism that facilitates efficient conduction band population in ZnO…
Elucidating the underlying principles behind band gap engineering is paramount for the successful implementation of semiconductors in photonic and optoelectronic devices. Recently it has been shown that the band gap of a wide and direct…
Due to its wide band gap and high carrier mobility, ZnO is an attractive material for light-harvesting and optoelectronic applications. Its functional efficiency, however, is strongly affected by defect-related in-gap states that open up…
Soft x-ray emission and absorption spectroscopy of the O K-edge are employed to investigate the electronic structure of wurtzite ZnO(0001). A quasiparticle band structure calculated within the GW approximation agrees well with the data,…
In this paper, temporal growth and morphological evolution of ZnO nano-colloids were studied by in-situ UV-Vis absorption spectroscopy and Transmission Electron Microscopy (TEM) respectively. Nucleation of the nanoparticles was observed to…