Cathodoluminescence Spectroscopy (cathodoluminescence + spectroscopy)

Distribution by Scientific Domains
Physics and Astronomy80%

Selected Abstracts

Fabrication and Optical Characteristics of Position-Controlled ZnO Nanotubes and ZnO/Zn0.8Mg0.2O Coaxial Nanotube Quantum Structure Arrays

ADVANCED FUNCTIONAL MATERIALS, Issue 10 2009
Jinkyoung Yoo
Abstract The position-controlled growth and structural and optical characteristics of ZnO nanotubes and their coaxial heterostructures are reported. To control both the shape and position of ZnO nanotubes, hole-patterned SiO2 growth-mask layers on Si(111) substrates with GaN/AlN intermediate layers using conventional lithography are prepared. ZnO nanotubes are grown only on the hole patterns at 600,°C by catalyst-free metal,organic vapor-phase epitaxy. Furthermore, the position-controlled nanotube growth method allows the fabrication of artificial arrays of ZnO-based coaxial nanotube single-quantum-well structures (SQWs) on Si substrates. In situ heteroepitaxial growth of ZnO and Zn0.8Mg0.2O layers along the circumference of the ZnO nanotube enable an artificial formation of quantum-well arrays in a designed fashion. The structural and optical characteristics of the ZnO nanotubes and SQW arrays are also investigated using synchrotron radiation X-ray diffractometry and photoluminescence and cathodoluminescence spectroscopy. [source]

Cathodoluminescence as a tool to determine the phosphorus concentration in diamond

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 9 2007
J. Barjon
Abstract In n-type diamond doped with phosphorus, exciton properties have been investigated by cathodoluminescence as a function of the phosphorus concentration. A series of homoepitaxial diamond layers were grown by microwave plasma-assisted chemical vapor deposition and doped with a liquid organic precursor of phosphorus (tertiarybutylphosphine). Their phosphorus concentration ranges from 5.2 × 1016 cm,3 to 3.3 × 1018 cm,3 as measured by secondary ion mass spectrometry. It is shown that the ratio between the luminescence intensities of the neutral phosphorus-bound exciton and the free exciton recombinations follows the donor concentration. A calibration graph is presented to determine the phosphorus contents in diamond with cathodoluminescence spectroscopy at 102 K. The influence of electrical compensation on the optical spectra is discussed. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Cathodoluminescence properties of zinc oxide nanoparticles

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 2 2004
M. R. Phillips
Abstract Zinc oxide nano-particles (25 nm) have been investigated by cathodoluminescence spectroscopy (300 nm,1700 nm) at 80 K and 300 K following thermal annealing in high purity H2/N2, N2, O2 and Ar gaseous atmospheres. The intensity of the ZnO near band edge peak was significantly increased after heat treatment in hydrogen. Conversely, thermal annealing in the other gas types decreased this emission. This effect is attributed to hydrogen passivation of competitive non-radiative defect centers, most likely bulk zinc vacancy centers. The appearance of a strong green emission centered at 2.4 eV following thermal annealing in all gas atmospheres is ascribed to the formation of bulk oxygen vacancy defects. A strong red shift of the near band edge emission with increasing beam current at 300 K is accredited to electron beam heating rather than to an increase in the carrier density. Electron beam heating is evidenced by the occurrence of a strong black body emission in the near infrared spectral region. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Effect of overgrowth conditions on the optical properties of lateral epitaxially overgrown a -plane GaN

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7-8 2010
T. J. Badcock
Abstract We investigate the optical properties of lateral epitaxially overgrown non-polar a -plane GaN using photoluminescence and spatially resolved cathodoluminescence spectroscopy. Despite the decreased density of extended defects relative to a -plane templates, in material overgrown at a low V:III ratio (57), the low temperature emission spectrum is very weak and is dominated by impurity bands centred at 2.92 and 2.25 eV. On subsequent overgrowth at a higher V:III ratio (260), the intensity of the near band edge emission increases by many orders of magnitude and a donor-acceptor pair band is seen. We suggest that the dramatic modification of the optical properties is related to the impurity or point-defect incorporation rate at the different V:III ratios employed. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Cathodoluminescence properties of InGaN codoped with Zn and Si

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2006
Y. Honda
Abstract An InGaN alloy co-doped with Zn and Si was grown by metal organic vapor phase epitaxy on a GaN templated silicon substrate and the luminesence (CL) properties are studied by cathodoluminescence spectroscopy. As the result of co-doping of Zn and Si, the CL intensity was extremely enhanced; enhancement in the peak intensity as well as the full-width at half maximum. The optimum doping density was estimated to be N(Zn) = 4.0 x 1019/cm3 and N(Si) = 8.0 x 1018/cm3. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]