Structural and Optical Properties of AlGaN/GaN Quantum-Well Structures Grown by MOCVD on Sapphire

1996 ◽  
Vol 449 ◽  
Author(s):  
R. Niebuhr ◽  
K. H. Bachem ◽  
D. Behr ◽  
C. Hoffmann ◽  
U. Kaufmann ◽  
...  
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Chemical Vapor ◽  
Interface Roughness ◽  
Organic Chemical ◽  
Quantum Well Structures ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Metal Organic ◽  
Step Flow Growth

ABSTRACTAlGaN/GaN single quantum wells (QW) have been grown on 2” sapphire substrates (c-plane) by metal-organic chemical vapor deposition (MOCVD). The well width was varied between 20 and 40 Å for barriers containing 4 % and 16 % of aluminium. Cathodoluminescence (CL) and Photoluminescence (PL) spectra of the samples show, as expected, a shift of the quantum well emission to higher energies with decreasing well width, whereas the barrier luminescence stays at constant energy. Examination of the QWs by resonant Raman spectroscopy tuned to the gap of the well, clearly shows the GaN A1(LO) phonon besides the AlGaN A1(LO) phonon from the barrier. For a well width of 20 Å we observe a shift of the A1(LO) GaN phonon indicating a certain degree of intermixing at the GaN/AlGaN interface. Atomic Force Microscopy (AFM) reveals that the layers are growing in a 2-dimensional step flow growth mode with step heights of 3 and 6 Å corresponding to mono- and biatomic steps. High Resolution Transmission Electron Microscopy (HRTEM) micrographs of the 40 Å well show a very low interface roughness of 1–2 atomic layers.

scholarly journals Optical Properties of Si-DOPED AlxGa1−xN/AlyGa1−yN (x=0.24−0.53, y=0.11) Multi-Quantum-Well Structures

1999 ◽  
Vol 4 (S1) ◽  
pp. 405-410
Author(s):  
H. Hirayama ◽  
Y. Aoyagi
Keyword(s):  
Quantum Well ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Quantum Well Structures ◽  
Si Doping ◽  
Active Layers ◽  
Metal Organic ◽  
Si Doped ◽  
Pl Emission ◽  
Multi Quantum Well

We demonstrate strong ultraviolet (UV) (280-330nm) photoluminescence (PL) emission from multi-quantum-well (MQW) structures consisting of AlGaN active layers fabricated by metal-organic chemical-vapor-deposition (MOCVD). Si-doping is shown to be very effective in order to enhance the PL emission of AlGaN QWs. We found that the optimum values of well thickness and Si-doping concentration of AlxGa1−xN/AlyGa1−yN (x=0.24−0.53, y=0.11) MQW structure for efficient emission were approximately 3nm and 2×1019cm−3, respectively. In addition, the PL intensities of AlGaN, GaN and InGaN quantum well structures are compared. We have found that the PL emission at 77K from a Al0.53Ga0.47N/Al0.11Ga0.89N MQW is as strong as that of InGaN QWs.

scholarly journals Density control of InP/GaInP quantum dots grown by metal-organic vapor-phase epitaxy

2018 ◽  
Vol 52 (4) ◽  
pp. 477
Author(s):  
D.V. Lebedev ◽  
N.A. Kalyuzhnyy ◽  
S.A. Mintairov ◽  
K.G. Belyaev ◽  
M.V. Rakhlin ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Height Distribution ◽  
Force Microscopy ◽  
Self Organized ◽  
Density Control ◽  
Atomic Force ◽  
Transmission Electron ◽  
Metal Organic

AbstractWe investigated structural and emission properties of self-organized InP/GaInP quantum dots (QD) grown by metal organic chemical vapor deposition using an amount of deposited In from 7 to 2 monolayers (ML). In the uncapped samples, using atomic force microscopy (AFM), we observed lateral sizes of 100–200 nm, together with a bimodal height distribution having maxima at ∼5 and ∼15 nm, which we denoted as QDs of type A and B, respectively; and reduction of the density of the type-B dots from 4.4 to 1.6 μm^–2. The reduction of the density of B-type dots were observed also using transmission electron microscopy of the capped samples. Using single dot low-temperature photoluminescence (PL) spectroscopy we demonstrated effects of Wigner localization for the electrons accumulated in these dots.

Optical Properties of Si-DOPED AlxGal-xN/AlyGal-yN (x=0.24-0.53, y=0.11) Multi-Quantum-Well Structures

1998 ◽  
Vol 537 ◽  
Author(s):  
H. Hirayama ◽  
Y. Aoyagi
Keyword(s):  
Quantum Well ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Quantum Well Structures ◽  
Si Doping ◽  
Active Layers ◽  
Metal Organic ◽  
Si Doped ◽  
Pl Emission ◽  
Multi Quantum Well

AbstractWe demonstrate strong ultraviolet (UV) (280-330nm) photoluminescence (PL) emission from multi-quantum-well (MQW) structures consisting of AlGaN active layers fabricated by metal-organic chemical-vapor-deposition (MOCVD). Si-doping is shown to be very effective in order to enhance the PL emission of AlGaN QWs. We found that the optimum values of well thickness and Si-doping concentration of AlxGal-xN/AlyGal-yN (x=0.24-0.53, y=0.11) MQW structure for efficient emission were approximately 3nm and 2×1019cm-3, respectively. In addition, the PL intensities of AlGaN, GaN and InGaN quantum well structures are compared. We have found that the PL emission at 77K from a Al0.53Ga0.47N/Al0.11Ga0.89N MQW is as strong as that of InGaN QWs.

Fabrication and Characterization of Stacked Self-Assembled In0.5Ga0.5As/GaAs Quantum Dots Grown by MOCVD

2014 ◽  
Vol 896 ◽  
pp. 215-218
Author(s):  
Didik Aryanto ◽  
Zulkafli Othaman ◽  
A. Khamim Ismail
Keyword(s):  
Quantum Dots ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Metal Organic ◽  
Self Assembled

Stacked self-assembled In0.5Ga0.5As/GaAs quantum dots (QDs) were grown using metal organic chemical vapor deposition (MOCVD). Atomic force microscopy (AFM), transmission electron microscopy (TEM) and high resolution X-ray diffraction (HR-XDR) show the effects of stacking on morphology and structure of QDs. Strains due to the buried QDs affect the shape and alignment of the successive layers. Capping of these QDs also determine the quality of the top most QDs structure.

Structural and electronic properties of defects in semiconductors

1995 ◽  
Vol 53 ◽  
pp. 4-5
Author(s):  
J.L. Batstone
Keyword(s):  
Semiconductor Device ◽  
Chemical Vapor ◽  
Misfit Strain ◽  
Organic Chemical ◽  
Extended Defects ◽  
Transmission Electron ◽  
Semiconductor Thin Films ◽  
Wide Range ◽  
Metal Organic ◽  
Film Substrate

The development of growth techniques such as metal organic chemical vapor deposition (MOCVD) and molecular beam epitaxy during the last fifteen years has resulted in the growth of high quality epitaxial semiconductor thin films for the semiconductor device industry. The III-V and II-VI semiconductors exhibit a wide range of fundamental band gap energies, enabling the fabrication of sophisticated optoelectronic devices such as lasers and electroluminescent displays. However, the radiative efficiency of such devices is strongly affected by the presence of optically and electrically active defects within the epitaxial layer; thus an understanding of factors influencing the defect densities is required.Extended defects such as dislocations, twins, stacking faults and grain boundaries can occur during epitaxial growth to relieve the misfit strain that builds up. Such defects can nucleate either at surfaces or thin film/substrate interfaces and the growth and nucleation events can be determined by in situ transmission electron microscopy (TEM).

Epitaxial Growth and Characterization of Nonpolar A-Plane AlGaN-Based Multiple Quantum Wells

2018 ◽  
Vol 934 ◽  
pp. 8-12
Author(s):  
Jian Guo Zhao ◽  
Xiong Zhang ◽  
Jia Qi He ◽  
Shuai Chen ◽  
Zi Li Wu ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Chemical Vapor ◽  
Multiple Quantum Wells ◽  
Modulation Method ◽  
Duty Ratio ◽  
Organic Chemical ◽  
Multiple Quantum ◽  
X Ray Diffraction ◽  
Metal Organic

A serious of non-polar a-plane AlGaN-based multiple quantum wells (MQWs) were successfully grown on the semi-polar r-plane sapphire substrate with metal organic chemical vapor deposition technology. Intense MQWs-related emission peaks at an emission wavelength covered from 277-294 nm were observed based on the photoluminescence measurement. It was found that the employment of the trimethyl-aluminum (TMAl) flow duty-ratio modulation method which was developed based on the two-way pulsed-flows growth technique played a crucial role to control the Al composition of the non-polar a-plane AlGaN epi-layers. The non-polar a-plane AlGaN-based MQWs were deposited with the new developed TMAl flow duty-ratio modulation technique. Evident-3th order X-ray diffraction (XRD) satellite peak was observed from the high resolution-XRD measurement, proving the successful growth of non-polar a-plane AlGaN-based MQWs with abrupt hetero-interfaces.

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