Surface Emission of InxGa1-x N/GaN Espaliers Grown by MOCVD under Different Optical Excitation

2012 ◽  
Vol 442 ◽  
pp. 393-397
Author(s):  
You Zhang Zhu ◽  
Yan Liu ◽  
Hong Xia Wang ◽  
Zhen Sun ◽  
Jin She Yuan
Keyword(s):  
Power Density ◽  
Chemical Vapor ◽  
Optical Excitation ◽  
Excitation Power ◽  
Organic Chemical ◽  
Light Sources ◽  
Excitation Power Density ◽  
Transmission Spectra ◽  
Surface Emission ◽  
The Difference

Photoluminescence properties of InGaN film grown on sapphire substrates by metal organic chemical vapor deposition(MOCVD) was experimentally Investigation. The x-ray diffraction(XRD), transmission spectra, PL spectrum were used. The result of XRD shows that the mole composition of In in the InGaN film is estimated be 0.2 approximately. The band gap of the sample is calculated to be 2.66eV. A clear oscillation from F-P cavity could be observed on transmission spectra. There are three main peaks from the surface emission InGaN espaliers being excited on different light sources and different excitation power density. which can be explained the broad PL come from the difference of In composition modulated by was modulated due to F-P cavity arising from surface of sample. . It is found that there is some relationship between the position of the peaks in the PL spectra, the wavelength and intensity of power density and the F-P cavity.PACS: 73.61.

scholarly journals Threshold increase and lasing inhibition due to hexagonal-pyramid-shaped hillocks in AlGaN-based DUV laser diodes on single-crystal AlN substrate

2021 ◽  
Author(s):  
Maki Kushimoto ◽  
Ziyi Zhang ◽  
Yoshio HONDA ◽  
Leo John Schowalter ◽  
Chiaki Sasaoka ◽  
...  
Keyword(s):  
Imaging Techniques ◽  
Laser Diodes ◽  
Optical Excitation ◽  
Threshold Current ◽  
Excitation Power ◽  
Threshold Current Density ◽  
Excitation Power Density ◽  
Threshold Excitation ◽  
The Difference ◽  
Hexagonal Pyramid

Abstract The presence of hexagonal-pyramid-shaped hillocks (HPHs) in AlGaN epitaxial films affects device character- istics; this effect is significant in DUV laser diodes (LDs) on AlN substrates, where the presence of HPHs under the p-electrode increases the threshold current density and inhibits the lasing. In this study, we investigated the difference between the lasing characteristics of LDs with and without HPHs. It was found that in the presence of HPHs, the threshold excitation power density increased and the slope efficiency decreased by optical excitation. To investigate the cause of these phenomena, we performed structural, optical, and electrical analyses of the HPHs. Various imaging techniques were used to directly capture the characteristics of the HPHs. As a result, we concluded that HPHs cause the degradation of LD characteristics due to a combination of structural, optical, and electrical factors.

Study of Optical Gain in Thick GaN Epilayers by Variable Stripe Length Technique

2005 ◽  
Vol 866 ◽  
Author(s):  
G. Tamulaitis ◽  
J. Mickevic ◽  
M. Shur ◽  
Q. Fareed ◽  
R. Gaska
Keyword(s):  
Light Propagation ◽  
Chemical Vapor ◽  
High Gain ◽  
Gain Medium ◽  
Excitation Power ◽  
Organic Chemical ◽  
Excitation Power Density ◽  
One Dimensional ◽  
Light Amplification ◽  
Stripe Length

AbstractWe report on the gain study in high-quality thick GaN layers using the Variable Stripe Length (VSL) technique. The layers were grown by Migration Enhanced Metal Organic Chemical Vapor Deposition (MEMOCVDTM). The amplification of light was investigated for the propagation directions along the layer surface (perpendicular to the c-axis of the crystal) and perpendicular to the layer (along the c-axis) for the layers with thicknesses up to 11 νm. By fitting the experimental stripe length dependence of the edge luminescence with one-dimensional description of light amplification in medium with positive gain, peak gain coefficients of up to 7300 cm-1 were estimated in GaN at the excitation power density of 2 MW/cm2. We discuss limitations of the VSL technique due to the assumption of one-dimensional light propagation and strong influence of gain saturation in a high-gain medium. The contribution of new gain modes after saturation of the highest-gain modes was observed. The optical gains in GaN samples with different carrier lifetimes (obtained using time-resolved photoluminescence and light-induced transient grating techniques) were compared.

The sensitization of laser-induced heat of Er3+ doped Y2O3 nanocrystals by codoped with Mn2+

2015 ◽  
Vol 29 (22) ◽  
pp. 1550158
Author(s):  
Yunfeng Bai ◽  
Minjie Luan ◽  
Linjun Li ◽  
Zhelong He ◽  
Dongyu Li
Keyword(s):  
Power Density ◽  
Thermal Emission ◽  
Energy Levels ◽  
Excitation Power ◽  
Threshold Power ◽  
Excitation Power Density ◽  
Ir Laser ◽  
Order Of Magnitude ◽  
Low Threshold ◽  
Density Threshold

Low threshold power density cw laser-induced heat has been observed in [Formula: see text] and [Formula: see text] codoped [Formula: see text] nanocrystals under excitation by a 980 nm IR laser. Codoped [Formula: see text] remarkably reduces the power density threshold of laser-induced heat compared with [Formula: see text] doped [Formula: see text] nanocrystals. When the excitation power density exceed [Formula: see text], [Formula: see text] codoped [Formula: see text] nanocrystals emit strong blackbody radiation. The thermal emission of [Formula: see text] should originate from the multiphonon relaxation between neighboring energy levels. One additional UC-PL enhancement is observed. The UC-PL intensity can be enhanced by an order of magnitude through high temperature calcination caused by light into heat.

UV Emission Mechanisms in Quaternary AlInGaN Epilayers and Multiple Quantum Wells

2002 ◽  
Vol 722 ◽  
Author(s):  
Mee-Yi Ryu ◽  
C. Q. Chen ◽  
E. Kuokstis ◽  
J. W. Yang ◽  
G. Simin ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Light Emitting Diode ◽  
Chemical Vapor ◽  
Excitation Power ◽  
Multiple Quantum Wells ◽  
Multiple Quantum ◽  
Excitation Power Density ◽  
Light Emitting ◽  
Uv Emission ◽  
Alloy Disorder

AbstractWe present the results on investigation and analysis of photoluminescence (PL) dynamics of quaternary AlInGaN epilayers and AlInGaN/AlInGaN multiple quantum wells (MQWs) grown by a novel pulsed metalorganic chemical vapor deposition (PMOCVD). The emission peaks in both AlInGaN epilayers and MQWs show a blueshift with increasing excitation power density. The PL emission of quaternary samples is attributed to recombination of carriers/excitons localized at band-tail states. The PL decay time increases with decreasing emission photon energy, which is a characteristic of localized carrier/exciton recombination due to alloy disorder. The obtained properties of AlInGaN materials grown by a PMOCVD are similar to those of InGaN. This indicates that the AlInGaN system is promising for ultraviolet applications such as the InGaN system for blue light emitting diode and laser diode applications.

Excitation-Power-Density Dependent ac Surface Photovoltages in Radiation-Damaged Si Wafer

1984 ◽  
Vol 23 (Part 1, No. 6) ◽  
pp. 778-779 ◽  
Author(s):  
Chusuke Munakata ◽  
Noriaki Honma ◽  
Hajime Hayakawa
Keyword(s):  
Power Density ◽  
Excitation Power ◽  
Excitation Power Density ◽  
Density Dependent ◽  
Si Wafer

Effect of excitation power density on the upconversion luminescence of LaF3:Yb3+, Er3+ nanocrystals

2009 ◽  
Vol 485 (1-2) ◽  
pp. 493-496 ◽  
Author(s):  
Yuqiu Qu ◽  
Xianggui Kong ◽  
Yajuan Sun ◽  
Qinghui Zeng ◽  
Hong Zhang
Keyword(s):  
Power Density ◽  
Upconversion Luminescence ◽  
Excitation Power ◽  
Excitation Power Density

Growth and Characterization of In-Based Nitride Compounds and their Double Heterostructures

1997 ◽  
Vol 468 ◽  
Author(s):  
V. A. Joshkin ◽  
J. C Roberts ◽  
E. L. Piner ◽  
M. K. Behbehani ◽  
F. G. McIntosh ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Growth Conditions ◽  
Excitation Power ◽  
Excitation Power Density ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
Recombination Lifetime ◽  
Pl Spectra ◽  
Double Heterostructures

ABSTRACTWe report on the growth and characterization of InGaN bulk films and AlGaN/InGaN/AlGaN double heterostructures (DHs). Good quality bulk InGaN films have been grown by metalorganic chemical vapor deposition (MOCVD) with up to 40% InN as characterized by x-ray diffraction. The effect of hydrogen in the growth ambient on the lnN% incorporation in the InGaN films is presented. Photoluminescence (PL) spectra of AlGaN/InGaN/AlGaN DHs exhibit emission wavelengths from the violet through yellow depending on the growth conditions of the active InGaN layer. The PL spectra are fairly broad both at room temperature and 20 K, and could be a result of native defects or impurity related transitions. We also observed a linear dependence between the PL intensity and excitation power density in the 0.001 W/cm2 to 10 MW/cm2 range. Time resolved PL of one of these DHs suggest a recombination lifetime on the order of 520 ps.

CRYSTALLINE PHASE SEPARATION OF InGaN LAYER MATERIALS PREPARED BY METALORGANIC CHEMICAL VAPOR DEPOSITION

2002 ◽  
Vol 16 (01n02) ◽  
pp. 268-274
Author(s):  
ZHE CHUAN FENG ◽  
TZUEN RONG YANG ◽  
RONG LIU ◽  
ANDREW THYE SHEN WEE
Keyword(s):  
Chemical Vapor Deposition ◽  
Phase Separation ◽  
Vapor Deposition ◽  
Secondary Ion Mass Spectrometry ◽  
Chemical Vapor ◽  
Excitation Power ◽  
Organic Chemical ◽  
X Ray Diffraction ◽  
Uniform Distributions ◽  
Metal Organic

Zn -doped InGaN thin films were epitaxied on the top of 1-2 micron thick GaN grown on sapphire by metal organic chemical vapor deposition, and studied by a combination of high resolution X-ray diffraction (HR-XRD), micro-photoluminescence (PL) and secondary ion mass spectrometry (SIMS). HRXRD exhibits a GaN band and a single band from InGaN for samples without phase separation, but two or more InGaN bands corresponding to different x(In) for samples with phase separation. PL emissions from InGaN spread over a wider energy ranges and were modulated by the interference effects. Excitation power dependence measurements reveal 2-sets of PL emissions for samples with phase separation, but only 1-set for samples without phase separation. SIMS data showed that phase separated InGaN:Zn films possess a high Zn concentration near the InGaN-GaN interface and non-uniform distributions of In and Zn contents, which are in contrast with data from InGaN:Zn films with no In -phase separation. These interesting results are correlated to the growth process and microstructural properties.

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