Stimulated Emission at 258 nm in AlN/AlGaN Quantum Wells Grown on Bulk AlN Substrates

2003 ◽  
Vol 764 ◽  
Author(s):  
R. Gaska ◽  
Q. Fareed ◽  
G. Tamulaitis ◽  
I. Yilmaz ◽  
M.S. Shur ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Emission Intensity ◽  
Chemical Vapour ◽  
Pump Intensity ◽  
Stimulated Emission ◽  
Structural Quality ◽  
Multiple Quantum ◽  
Sample Edge ◽  
Intensity Saturation ◽  
Stripe Length

AbstractWe report on observation of stimulated emission at 258 nm in AlN/AlGaN multiple quantum wells. The structures were grown over Al-face single crystal bulk AlN substrates. AlN/AlGaN structures with 50% of Al in the well material were grown using low-pressure metalorganic chemical vapour deposition. Characterization by using X-ray, AFM, SEM, and photoluminescence techniques indicated high structural quality of the structures. The stimulated emission was measured using the variable stripe length method under excitation by 4-ns-long pulses of the fifth harmonic of Nd:YAG laser radiation at 213 nm (5.82 eV). The stimulated emission exhibited a characteristic superlinear dependence of emission intensity on the pump intensity as well as an exponential increase of the sample-edge emission intensity with increasing stripe length up to ∼430 μm and the intensity saturation beyond this range. The observation of stimulated emission at 258 nm is very promising for the future development of III-nitride-based deep-UV laser diodes on bulk AlN substrates.

Characterisation of multilayer materials using a position-sensitive atom probe

1990 ◽  
Vol 48 (4) ◽  
pp. 624-625
Author(s):  
RAD Mackenzie ◽  
G D W Smith ◽  
A. Cerezo ◽  
J A Liddle ◽  
CRM Grovenor ◽  
...  
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Spatial Information ◽  
Chemical Vapour ◽  
Atom Probe ◽  
Organic Chemical ◽  
Growth Stages ◽  
Multiple Quantum ◽  
Quartz Wool ◽  
Position Sensitive

The position sensitive atom probe (POSAP), described briefly elsewhere in these proceedings, permits both chemical and spatial information in three dimensions to be recorded from a small volume of material. This technique is particularly applicable to situations where there are fine scale variations in composition present in the material under investigation. We report the application of the POSAP to the characterisation of semiconductor multiple quantum wells and metallic multilayers.The application of devices prepared from quantum well materials depends on the ability to accurately control both the quantum well composition and the quality of the interfaces between the well and barrier layers. A series of metal organic chemical vapour deposition (MOCVD) grown GaInAs-InP quantum wells were examined after being prepared under three different growth conditions. These samples were observed using the POSAP in order to study both the composition of the wells and the interface morphology. The first set of wells examined were prepared in a conventional reactor to which a quartz wool baffle had been added to promote gas intermixing. The effect of this was to hold a volume of gas within the chamber between growth stages, leading to a structure where the wells had a composition of GalnAsP lattice matched to the InP barriers, and where the interfaces were very indistinct. A POSAP image showing a well in this sample is shown in figure 1. The second set of wells were grown in the same reactor but with the quartz wool baffle removed. This set of wells were much better defined, as can be seen in figure 2, and the wells were much closer to the intended composition, but still with measurable levels of phosphorus. The final set of wells examined were prepared in a reactor where the design had the effect of minimizing the recirculating volume of gas. In this case there was again further improvement in the well quality. It also appears that the left hand side of the well in figure 2 is more abrupt than the right hand side, indicating that the switchover at this interface from barrier to well growth is more abrupt than the switchover at the other interface.

Ultraviolet Stimulated Emission From Optically Pumped AlGaN/AlGaN Multiple Quantum Wells on Pulsed Laterally Overgrown $a$-Plane GaN

2011 ◽  
Vol 4 (8) ◽  
pp. 082103 ◽  
Author(s):  
Mohamed Lachab ◽  
Krishnan Balakrishnan ◽  
Bin Zhang ◽  
Joe Dion ◽  
Qhalid Fareed ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Stimulated Emission ◽  
Multiple Quantum Wells ◽  
Multiple Quantum ◽  
Optically Pumped

Ultraviolet Stimulated Emission in GaN/AlGaN Multiple Quantum Wells

1998 ◽  
Vol 264-268 ◽  
pp. 1433-1436
Author(s):  
L. Calcagnile ◽  
G. Coli ◽  
D. Rinaldi ◽  
R. Cingolani ◽  
H. Tang ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Stimulated Emission ◽  
Multiple Quantum Wells ◽  
Multiple Quantum

scholarly journals Epitaxial Growth and Optically Pumped Stimulated Emission in AlGaN/InGaN Ultraviolet Multi-Quantum-Well Structures

2020 ◽  
Vol 49 (4) ◽  
pp. 2326-2331
Author(s):  
Ping Chen ◽  
Young Jae Park ◽  
Yuh-Shiuan Liu ◽  
Theeradetch Detchprohm ◽  
P. Douglas Yoder ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Thermal Effect ◽  
Epitaxial Growth ◽  
Growth Temperature ◽  
Optimal Growth ◽  
State Density ◽  
Stimulated Emission ◽  
Multiple Quantum ◽  
Quantum Well Structures ◽  
Localized State

AbstractThe thermal effect of the growth temperature on interface morphology and stimulated emission in ultraviolet AlGaN/InGaN multiple quantum wells (MQWs) are experimentally investigated. During the MOCVD epitaxial growth of AlGaN/InGaN MQWs, the ramping rate from a lower temperature for InGaN quantum wells (QWs) to a higher one for AlGaN quantum barriers (QBs) is intentionally changed from 1.0°C/s to 4.0°C/s. Atomic force microscopy images show that the surface morphology of InGaN QWs, which is improved by a thermal effect when the growth temperature rises to the set value of the AlGaN QBs, varies with different temperature ramping rates. The results of stimulated emission indicate that the threshold pumping power density of MQWs is decreased with increasing temperature ramping rate from 1.0°C/s to 3.0°C/s and then slightly increased when the ramping rate is 4.0°C/s. This phenomenon is believed to result from the thermal degradation effect during the temperature ramp step. A long-time high-temperature annealing will reduce the density of indium-rich microstructures as well as the corresponding localized state density, which is assumed to contribute to the radiative recombination in the InGaN QWs. Given the great difference between optimal growth temperatures for AlGaN and InGaN layers, a higher ramping rate would be more appropriate for the growth of ultraviolet AlGaN/InGaN MQWs.

scholarly journals Dimension- and position-controlled growth of GaN microstructure arrays on graphene films for flexible device applications

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dongha Yoo ◽  
Keundong Lee ◽  
Youngbin Tchoe ◽  
Puspendu Guha ◽  
Asad Ali ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Stimulated Emission ◽  
Multiple Quantum ◽  
Controlled Growth ◽  
Light Emitting ◽  
Graphene Films ◽  
Device Applications ◽  
Electron Microscopes ◽  
Cu Foil ◽  
Foil Substrate

AbstractThis paper describes the fabrication process and characteristics of dimension- and position-controlled gallium nitride (GaN) microstructure arrays grown on graphene films and their quantum structures for use in flexible light-emitting device applications. The characteristics of dimension- and position-controlled growth, which is crucial to fabricate high-performance electronic and optoelectronic devices, were investigated using scanning and transmission electron microscopes and power-dependent photoluminescence spectroscopy measurements. Among the GaN microstructures, GaN microrods exhibited excellent photoluminescence characteristics including room-temperature stimulated emission, which is especially useful for optoelectronic device applications. As one of the device applications of the position-controlled GaN microrod arrays, we fabricated light-emitting diodes (LEDs) by heteroepitaxially growing InxGa1−xN/GaN multiple quantum wells (MQWs) and a p-type GaN layer on the surfaces of GaN microrods and by depositing Ti/Au and Ni/Au metal layers to prepare n-type and p-type ohmic contacts, respectively. Furthermore, the GaN microrod LED arrays were transferred onto Cu foil by using the chemical lift-off method. Even after being transferred onto the flexible Cu foil substrate, the microrod LEDs exhibited strong emission of visible blue light. The proposed method to enable the dimension- and position-controlled growth of GaN microstructures on graphene films can likely be used to fabricate other high-quality flexible inorganic semiconductor devices such as micro-LED displays with an ultrahigh resolution.

Study of Near-Threshold Gain Mechanisms in MOCVD-Grown GaN Epilayers and InGaN/GaN Heterostructures

1999 ◽  
Vol 572 ◽  
Author(s):  
S. Bidnyk ◽  
T. J. Schmidt ◽  
B. D. Little ◽  
J. J. Song
Keyword(s):  
Quantum Wells ◽  
Stimulated Emission ◽  
Multiple Quantum Wells ◽  
Multiple Quantum ◽  
Optically Pumped ◽  
Electron Hole ◽  
Electron Hole Plasma ◽  
Narrow Emission ◽  
Threshold Gain ◽  
Near Threshold

ABSTRACTWe report the results of an experimental study on near-threshold gain mechanisms in optically pumped GaN epilayers and InGaN/GaN heterostructures at temperatures as high as 700 K. We show that the dominant near-threshold gain mechanism in GaN epilayers is inelastic excitonexciton scattering for temperatures below ∼ 150 K, characterized by band-filling phenomena and a relatively low stimulated emission (SE) threshold. An analysis of both the temperature dependence of the SE threshold and the relative shift between stimulated and band-edge related emission indicates electron-hole plasma is the dominant gain mechanism for temperatures exceeding 150 K. The dominant mechanism for SE in InGaN epilayers and InGaN/GaN multiple quantum wells was found to be the recombination of carriers localized at potential fluctuations resulting from nonuniform indium incorporation. The SE spectra from InGaN epilayers and multiple quantum wells were comprised of extremely narrow emission lines and no spectral broadening of the lines was observed as the temperature was raised from 10 K to over 550 K. Based on the presented results, we suggest a method for significantly reducing the carrier densities needed to achieve population inversion in GaN, allowing for the development of GaNactive-medium laser diodes.

Stimulated emission characteristics of InGaN/GaN multiple quantum wells: Excitation length and excitation density dependence

1998 ◽  
Vol 73 (25) ◽  
pp. 3689-3691 ◽  
Author(s):  
T. J. Schmidt ◽  
S. Bidnyk ◽  
Yong-Hoon Cho ◽  
A. J. Fischer ◽  
J. J. Song ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Density Dependence ◽  
Stimulated Emission ◽  
Multiple Quantum Wells ◽  
Excitation Density ◽  
Emission Characteristics ◽  
Multiple Quantum
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