Exciton Spectra of AlN Epitaxial Films

2001 ◽  
Vol 693 ◽  
Author(s):  
T. Onuma ◽  
S. F. Chichibu ◽  
T. Sota ◽  
K. Asai ◽  
S. Sumiya ◽  
...  
Keyword(s):  
Sapphire Substrate ◽  
Characteristic Temperature ◽  
Longitudinal Optical ◽  
Epitaxial Films ◽  
Longitudinal Optical Phonon ◽  
Bohr Radius ◽  
Spectral Lineshape ◽  
Resonance Energies ◽  
Excitonic Emission ◽  
Excitonic Resonance

AbstractExcitonic resonance energies in a C-plane AlN epilayer on the (0001) sapphire substrate grown by low-pressure metalorganic vapor phase epitaxy were determined as a function of temperature by means of optical reflectance (OR) and cathodoluminescence (CL) measurements. The OR spectra exhibited distinct reflectance anomalies at the photon energies just above the multiple internal reflection fringes, and the spectral lineshape was fitted considering A (???u7v7c) and BC (???9v,???17v7c) exciton transitions. The energies of them at 0 K were obtained to be 6.211 and 6.266 eV, giving the crystal field splitting (Δcr) of approximately 55 meV. The AlNfilm exhibited an excitonic emission even at 300 K, which is due to the small Bohr radius of excitons and large longitudinal optical phonon energies. The Einstein characteristic temperature Q E was estimated to be 580 K.

Longitudinal-optical phonon hole-plasmon coupled modes in heavily doped p-type GaSb:Zn epitaxial films

2006 ◽  
Vol 50 (3) ◽  
pp. 403-410
Author(s):  
Z. G. Hu ◽  
M. B.M. Rinzan ◽  
A. G.U. Perera ◽  
Y. Paltiel ◽  
A. Raizman ◽  
...  
Keyword(s):  
Optical Phonon ◽  
Longitudinal Optical ◽  
Epitaxial Films ◽  
Longitudinal Optical Phonon ◽  
Coupled Modes ◽  
Heavily Doped ◽  
P Type

Longitudinal optical phonon-plasmon-coupled modes in epitaxial GaN films on sapphire substrate

2000 ◽  
Author(s):  
Z.F. Li ◽  
Wei Lu ◽  
H.-J. Ye ◽  
Xianzhang Yuan ◽  
Shuechu Shen ◽  
...  
Keyword(s):  
Sapphire Substrate ◽  
Optical Phonon ◽  
Longitudinal Optical ◽  
Longitudinal Optical Phonon ◽  
Coupled Modes

Reducing exciton–longitudinal optical phonon coupling with increasing Mg incorporation in MgZnO powders

2007 ◽  
Vol 102 (12) ◽  
pp. 123504 ◽  
Author(s):  
Ching-Ju Pan ◽  
Kuo-Feng Lin ◽  
Wei-Tse Hsu ◽  
Wen-Feng Hsieh
Keyword(s):  
Optical Phonon ◽  
Longitudinal Optical ◽  
Longitudinal Optical Phonon ◽  
Phonon Coupling

The effect of low temperature coating and annealing on structural and optical properties of CdSe/CdS core/shell QDs

2016 ◽  
Vol 55 (4) ◽  
Author(s):  
Maya Isarov ◽  
N. Grumbach ◽  
Georgy I. Maikov ◽  
Jenya Tilchin ◽  
Youngjin Jang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Interface Layer ◽  
Longitudinal Optical ◽  
Band Gap Energy ◽  
Longitudinal Optical Phonon ◽  
Core Shell ◽  
Temperature Dependent ◽  
Structural And Optical Properties ◽  
Wide Range ◽  
Temperature Dependent Properties

This paper presents the optical temperature dependent properties, over a wide range of temperatures from 4 to 300 K, of new CdSe/CdS core/shell colloidal quantum dots (QDs) with varying shell thickness coated and annealed at low temperature. It was demonstrated that low temperature coating and annealing processes enhanced the photoluminescence (PL) quantum yield accompanied by variation in the QDs structure, formation of an alloyed interface layer, suppression of the number of defects at the CdSe/CdS interface, band gap energy red-shift, narrowing of CdS longitudinal optical phonon band, and decrease of the PL inhomogeneous broadening parameter.

scholarly journals Depth Profiling of Ion-Implanted 4H–SiC Using Confocal Raman Spectroscopy

Crystals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 131
Author(s):  
Ying Song ◽  
Zongwei Xu ◽  
Tao Liu ◽  
Mathias Rommel ◽  
Hong Wang ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Epitaxial Layer ◽  
Depth Profiling ◽  
Longitudinal Optical ◽  
Longitudinal Optical Phonon ◽  
Objective Lens ◽  
Substrate Layer ◽  
Depth Analysis ◽  
Confocal Raman ◽  
Ion Implanted

For silicon carbide (SiC) processed by ion-implantation, dedicated test structure fabrication or destructive sample processing on test wafers are usually required to obtain depth profiles of electrical characteristics such as carrier concentration. In this study, a rapid and non-destructive approach for depth profiling is presented that uses confocal Raman microscopy. As an example, a 4H–SiC substrate with an epitaxial layer of several micrometers thick and top layer in nanoscale that was modified by ion-implantation was characterized. From the Raman depth profiling, longitudinal optical (LO) mode from the epitaxial layer and longitudinal optical phonon-plasmon coupled (LOPC) mode from the substrate layer can be sensitively distinguished at the interface. The position profile of the LOPC peak intensity in the depth direction was found to be effective in estimating the thickness of the epitaxial layer. For three kinds of epitaxial layer with thicknesses of 5.3 μm, 6 μm, and 7.5 μm, the average deviations of the Raman depth analysis were −1.7 μm, −1.2 μm, and −1.4 μm, respectively. Moreover, when moving the focal plane from the heavily doped sample (~1018 cm−3) to the epitaxial layer (~1016 cm−3), the LOPC peak showed a blue shift. The twice travel of the photon (excitation and collection) through the ion-implanted layer with doping concentrations higher than 1 × 1018 cm−3 led to a difference in the LOPC peak position for samples with the same epitaxial layer and substrate layer. Furthermore, the influences of the setup in terms of pinhole size and numerical aperture of objective lens on the depth profiling results were studied. Different from other research on Raman depth profiling, the 50× long working distance objective lens (50L× lens) was found more suitable than the 100× lens for the depth analysis 4H–SiC with a multi-layer structure.

Sign in / Sign up

Export Citation Format

Share Document