The role of intrinsic point defects on radiative recombination in Cu(In,Ga)Se2 thin films was investigated by photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopies. Experiments were performed on device-grade polycrystalline layers and single crystal thin films. PL transitions identified by others as indicating a shallow state with an ionization energy of ~16 meV is propos...

CdSe/CdS/ZnS core-shell-shell quantum dots (QDs) were synthesized by using a solution process. High-resolution transmission electron microscopy images and energy dispersive spectroscopy profiles confirmed that stoichiometric CdSe/CdS/ZnS core-shell-shell QDs were formed. Ultraviolet-visible absorption and photoluminescence (PL) spectra of CdSe/CdS/ZnS core-shell-shell QDs showed the dominant ex...

Understanding the doping mechanism that involves substantial charge transfer between carbon nanotubes and chemical adsorbent is of critical importance for both basic scientific knowledge and nanodevice applications. Nevertheless, it is difficult to estimate the modification of electronic structures of the doped carbon nanotubes. Here we report measurements of electrochemical potentials of n-dop...

Porous Silicon (PS) samples have been prepared by electrochemical anodization of p-type silicon wafer by varying HF concentrations in the electrolytic solution. The structural, surface morphological, optical and surface composition analysis of the prepared samples were done by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Photoluminescence (PL) and Fourier transform infr...

We present a comprehensive study of the optical characteristics of (Al, In)GaN epilayers measured by photoluminescence (PL), integrated PL intensity, and timeresolved PL spectroscopy. For not only InGaN, but also AlGaN epilayers with large Al content, we observed an anomalous PL temperature dependence: (i) an “S-shaped” PL peak energy shift (decrease-increase-decrease) and (ii) an “inverted S-s...

Porous Silicon (PS) samples have been prepared by electrochemical anodization of p-type silicon wafer by varying HF concentrations in the electrolytic solution. The structural, surface morphological, optical and surface composition analysis of the prepared samples were done by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Photoluminescence (PL) and Fourier transform infr...

This paper reports on experimental and theoretical investigations of atypical temperature-dependent photoluminescence properties of multi-stacked InAs quantum dots in close proximity to InGaAs strain-relief underlying quantum well. The InAs/InGaAs/GaAs QD heterostructure was grown by solid-source molecular beam epitaxy (SS-MBE) and investigated via photoluminescence (PL), spectroscopic ellipsom...

Photoluminescence properties of a quantum system consisting of four different size GaAs quantum wells (Lz=15, 7, 4.5 and 3 nm) clad by 50 nm thick Al0.24Ga0.76As barriers have been investigated by steady-state and time-resolved (TR) photoluminescence (PL) experiments at 13-300 K. It is found that the low temperature PL emission energy distribution is not uniform over the four excitonic emission...

We report the synthesis of highly luminescent, water soluble quantum clusters (QCs) of gold, which are stabilized by an iron binding transferrin family protein, lactoferrin (Lf). The synthesized AuQC@Lf clusters were characterized using UV-Visible spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), photoluminescence (PL), matrix assisted laser desorptio...

in this research zinc oxide (zno) nano-crystalline powders were prepared by sol-gel method using zinc acetate. the zno nanoparticles were characterized by x-ray diffraction (xrd), scanning electron microscopy (sem), ultraviolet-visible (uv-vis), fourier transform infra-red (ft-ir) and energy dispersive x-ray (edx) spectroscopy. the structure of nanoparticles was studied using xrd pattern. the c...