Related Experiment Video
Updated: Jun 21, 2026
06:50
Synthesis of Hierarchical ZnO/CdSSe Heterostructure Nanotrees
Published on: November 29, 2016
Correlations between surface-excitonic emission bands in ZnO nanowires
L Wischmeier1, T Voss, I Rückmann
1Institute of Solid State Physics, University of Bremen, PO Box 330 440, D-28334 Bremen, Germany.
Nanotechnology
|July 29, 2009
Summary
We investigated surface-related photoluminescence in ZnO nanowires. The study found a direct correlation between emission band A and surface-exciton band SX, attributing band A to defects.
Area of Science:
- Materials Science
- Nanotechnology
- Solid State Physics
Background:
- Zinc oxide (ZnO) nanowires exhibit unique optical properties crucial for electronic and optoelectronic applications.
- Surface-related photoluminescence (PL) in ZnO nanowires is complex and often linked to defects.
- Understanding these surface emissions is key to controlling ZnO nanowire functionality.
Purpose of the Study:
- To investigate the correlated spectral properties of two surface-related photoluminescence bands in ZnO nanowires.
- To elucidate the relationship between the surface-related emission band A and the surface-exciton band SX.
- To determine the origin of the surface-related emission band A.
Main Methods:
- Photoluminescence (PL) spectroscopy to analyze spectral properties.
- Temperature-dependent PL measurements to study emission intensity variations.
- Time-resolved PL to measure photoluminescence decay times.
- Analysis of thermal activation energies.
Main Results:
- A direct correlation was observed between the spectral position and temperature-dependent intensity of emission band A and the surface-exciton band SX.
- Thermal activation energies for both bands were measured.
- The photoluminescence decay time of emission band A was determined using time-resolved PL data.
Conclusions:
- Emission band A is assigned to excitons bound to structural defects within the surface layer of ZnO nanowires.
- The observed correlations suggest a strong interaction between surface excitons and defect-bound excitons.
- This finding provides insight into defect-related optical phenomena in ZnO nanostructures.
More Related Videos
Related Concept Videos
01:14Photoluminescence: Applications
Photoluminescence offers a wide range of applications due to its inherent sensitivity and selectivity. This technique allows for both direct and indirect analyses of the analyte. Direct quantitative analysis is possible when the analyte exhibits a favorable quantum yield for fluorescence or phosphorescence. However, an indirect analysis may be feasible if the analyte is not fluorescent or phosphorescent, or if the quantum yield is unfavorable. Indirect methods include reacting the analyte with...
01:23Photoluminescence: Fluorescence and Phosphorescence
Photoluminescence is a process where a molecule absorbs light energy and re-emits it in the form of light. This phenomenon occurs when a substance absorbs photons, promoting its electrons to higher energy level excited states, followed by a relaxation process in which the electrons return to their original ground state energy levels and emit light. Photoluminescence is widely observed in various materials, including semiconductors, and organic and inorganic compounds.
A pair of electrons in a...
A pair of electrons in a...
01:26Variables Affecting Phosphorescence and Fluorescence
Fluorescence and phosphorescence are essential phenomena in fields like analytical chemistry, biological imaging, and materials science, where they detect molecular properties and visualize cellular structures. Understanding the variables that influence these luminescent behaviors is crucial for maximizing accuracy and efficiency in their applications. These variables can broadly be grouped into chemical structure, solvent properties, and external conditions, each playing a distinct role in...
01:14Molecular Spectroscopy: Absorption and Emission
Molecules possess discrete energy levels called quantum states. Unlike atoms, which have simpler energy levels, molecules possess additional rotational and vibrational energy levels. Each energy level is separated by an energy gap, with the gaps between adjacent electronic, vibrational, and rotational levels varying significantly. The three types of energy levels in a diatomic molecule are shown in Figure 1.
01:16UV–Vis Spectroscopy: Molecular Electronic Transitions
In Ultraviolet–Visible (UV–Vis) spectroscopy, the absorption of electromagnetic radiation is used to probe the electronic structure of molecules. This technique provides insights into molecular electronic transitions, particularly the movement of electrons between different molecular orbitals. Radiation is absorbed if the energy of the electromagnetic radiation passing through the molecule is precisely equal to the energy difference between the excited and ground states. During this process,...
01:11P-N junction
A p-n junction is formed when p-type and n-type semiconductor materials are joined together. At the interface of the p-n junction, holes from the p-side and electrons from the n-side begin to diffuse into the opposite sides due to the concentration gradient. This diffusion of carriers leads to a region around the junction where there are no free charge carriers, known as the depletion region. The charge density within the depletion region for the n-side and p-side can be described by the...