Optoelectronic Device Applications of Self-Organized In(Ga,Al)As/Ga(Al)As Quantum Dots

2000 ◽  
Vol 618 ◽  
Author(s):  
P. Bhatiacharya ◽  
S. Krishna ◽  
D. Zhu ◽  
J. Phillips ◽  
D. Klotzkin ◽  
...  
Keyword(s):  
Quantum Dots ◽  
High Speed ◽  
Energy Levels ◽  
Relaxation Times ◽  
Optoelectronic Device ◽  
Infrared Emission ◽  
Electronic Energy ◽  
Tunneling Time ◽  
Self Organized ◽  
Electro Optic

ABSTRACTSelf-organized growth of strained semiconductor heterostructures has enabled the realization of ordered arrays of quantum dots that can be incorporated into the active region of electronic and optoelectronic devices. Highly uniform In(Ga)As/Ga(Al)As with greatly reduced photoluminescence linewidths (FWHM=19 meV, T=17K) have been grown and characterized. Various aspects of carrier dynamics in these dots, such as measurement of carrier relaxation times and the modulation bandwidths of quantum dot lasers, estimation of the tunneling time in vertically coupled dots along with tuning of the intersubband electronic energy levels have also been studied. The favorable relaxation times can be exploited to realize far infrared emission and detection based on intersubband transitions in the dots. The optoelectronic properties of the dots and the dynamics of carriers therein are also extremely attractive for high-speed wavelength switching and the design of electro-optic modulators. The electro-optic coefficients in the quantum dots have been measured and the linear E-O coefficient, r1 =2.6 ×10−11m/V, is found to be comparable to that in LiNbO3

Electronic energy levels and energy relaxation mechanisms in self-organized InAs/GaAs quantum dots

1996 ◽  
Vol 54 (24) ◽  
pp. 17738-17744 ◽  
Author(s):  
M. J. Steer ◽  
D. J. Mowbray ◽  
W. R. Tribe ◽  
M. S. Skolnick ◽  
M. D. Sturge ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Energy Levels ◽  
Energy Relaxation ◽  
Electronic Energy ◽  
Self Organized ◽  
Electronic Energy Levels

STRAIN DISTRIBUTION AND ELECTRONIC STRUCTURE OF SELF-ORGANIZED InAs/GaAs QUANTUM DOTS

2009 ◽  
Vol 18 (04) ◽  
pp. 553-560
Author(s):  
YUMIN LIU ◽  
ZIHUAN XU ◽  
ZHONGYUAN YU ◽  
BOYONG JIA ◽  
WENJUAN LU ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Electronic Structure ◽  
Quantum Dot ◽  
Strain Distribution ◽  
Energy Levels ◽  
Electronic Energy ◽  
Conduction Band Edge ◽  
Three Dimension ◽  
Self Organized ◽  
Piezoelectric Effects

This paper presents a finite element method for calculating the strain distribution, piezoelectric effects and their influences on the electronic structure of self-organized InAs/GaAs quantum dots. The models used for strain calculations are based on the continuum elastic theory, which is capable of treating the quantum dot of arbitrary shapes. A truncated pyramid shaped quantum dot model including the wetting layer is adopted in this work. The electronic energy levels of the InAs/GaAs systems are calculated by solving the three-dimension effective mass Schrödinger equation including the influences on the modification of conduction band edge due to the strain and piezoelectricity. The calculated results indicate that both strain and piezoelectric effects should be considered, especially in treating the electronic structure and optical characteristics for device applications.

Biologically Engineered Quantum Dots for Biomedical Applications

2008 ◽  
Vol 1095 ◽  
Author(s):  
Ganna Chornokur ◽  
Sergei Ostapenko ◽  
Yusuf Emirov ◽  
Nadezhda Korsunska ◽  
Abraham Wolcott ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Energy Levels ◽  
Local Stress ◽  
Blue Shift ◽  
Spectral Shift ◽  
Electronic Energy ◽  
Transmission Electron ◽  
Solid Substrates ◽  
Electronic Energy Levels ◽  
Electrophoresis Technique

AbstractWe report on a short-wavelength, “blue” spectral shift of the photoluminescence (PL) spectrum in CdSeTe/ZnS core/shell quantum dots (QDs) caused by bioconjugation with several monoclonal cancer related antibodies (ABs). Scanning PL spectroscopy was performed on samples dried on solid substrates at various temperatures. The influence of the AB chemical origin on the PL spectral shift was observed. The conjugation QD-AB reaction was confirmed using the agarose gel electrophoresis technique. The spectral shift is strongly increased and the process facilitated when the samples are dried above room temperature. The PL spectroscopic mapping revealed a profile of the PL spectral shift across the dried QD-AB spot. Transmission Electron Microscopy analyses of the samples were performed to reveal the shape and size of individual QDs. A mechanism of the “blue” shift is attributed to changes in the QD electronic energy levels caused by local stress field applied to the bio-conjugated QD.

Electronic Energy Levels in an Asymmetric Quantum-Dots-in-a-Well Structure for Infrared Photodetectors

2008 ◽  
Vol 25 (7) ◽  
pp. 2645-2648 ◽  
Author(s):  
Wang Zhi-Cheng ◽  
Xu Bo ◽  
Chen Yong-Hai ◽  
Shi Li-Wei ◽  
Liang Zhi-Mei ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Energy Levels ◽  
Electronic Energy ◽  
Infrared Photodetectors ◽  
Asymmetric Quantum ◽  
Electronic Energy Levels ◽  
Asymmetric Quantum Dots

A consolidated account of electrochemical determination of band structure parameters in II–VI semiconductor quantum dots: a tutorial review

2019 ◽  
Vol 21 (9) ◽  
pp. 4695-4716 ◽  
Author(s):  
Pravin Popinand Ingole
Keyword(s):  
Quantum Dots ◽  
Band Structure ◽  
Electronic Band Structure ◽  
Energy Levels ◽  
Electrochemical Determination ◽  
Electronic Energy ◽  
Semiconductor Quantum Dots ◽  
Electronic Band ◽  
Nano Structure ◽  
Electronic Energy Levels

Probing absolute electronic energy levels in semiconductor quantum dots (Q-dots) is crucial for engineering their electronic band structure and hence for precise design of composite nano-structure based devices.

Quantum Dots in GaInP/GaInAs/GaAs for Infrared Sensing

2006 ◽  
Vol 51 ◽  
pp. 201-208 ◽  
Author(s):  
H. Lim ◽  
S. Tsao ◽  
M. Taguchi ◽  
W. Zhang ◽  
A.A. Quivy ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Integrated Circuit ◽  
Infrared Detector ◽  
Energy Levels ◽  
Chemical Vapor ◽  
Electronic Energy ◽  
Cryogenic Cooling ◽  
Device Structure ◽  
Infrared Sensing ◽  
Self Assembled

Nanotechnology is occurring simultaneously in almost every field with strong interdisciplinary applications which have unique and important characteristics for potential novel and high performance devices. Quantum dots grown by epitaxial self-assembly via Stranski- Krastanov growth mode have many favorable properties for infrared sensing. Because of their very small size and three-dimensional confinement, the electronic energy levels are quantized and discrete. These quantum effects lead to a unique property, “phonon bottleneck”, which might enable the high operating temperature of infrared sensing which usually requires cryogenic cooling. Here we report a focal plane array (FPA) based on an epitaxial self-assembled quantum dot infrared detector (QDIP). The device structure containing self-assembled In0.68Ga0.32As quantum dots with a density around 3×1010 cm-2 was grown by low-pressure metalorganic chemical vapor deposition (LP-MOCVD). Using different structures, we successfully developed QDIPs with a peak photoresponse around 5 μm and 9 μm. High peak detectivities were achieved at 77 K from both QDIPs. By stacking both device structures, we demonstrated a two-color QDIP whose peak detection wavelength could be tuned from 5 μm to 9 μm by changing the bias. 256×256 detector arrays based on 5 μm and 9 μm-QDIPs were fabricated with standard photolithography, dry etching and hybridization to a read-out integrated circuit (ROIC). We demonstrated thermal imaging from our FPAs based on QDIPs.

QUANTUM DOT SEMICONDUCTOR LASERS

1998 ◽  
Vol 09 (04) ◽  
pp. 1081-1107
Author(s):  
PALLAB BHATTACHARYA
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Semiconductor Lasers ◽  
High Speed ◽  
Room Temperature ◽  
Growth Parameters ◽  
Light Emitters ◽  
Self Organized ◽  
Speed Performance ◽  
Ridge Waveguide Lasers

The formation of coherently strained islands during the growth of strained heterostructures has been exploited to form an array of quantum dots. The shape and size of the islands vary with growth parameters, but exhibit the electronic properties of zero-dimensional systems. One or multiple, vertically coupled, layers of such quantum dots can form the gain region of a separately confined heterostructure (SCH) laser. The properties of such InGaAs/GaAs self-organized quantum dot lasers are described here. The lasers exhibit temperature independent operation up to 100 K and beyond. Typical threshold currents of 200 μm long room temperature lasers vary from 6 to 20 mA. The small-signal modulation bandwidths of ridge waveguide lasers are 5–7.5 GHz at 300 K and increased to >20 GHz at 80 K. We believe that electron-hole scattering intrinsically limits the high-speed performance of these devices, in spite of differential gains as high as ~ 7× 10-14 cm2 at room temperature. Wavelength switching is demonstrated in these devices and preliminary results on long-wavelengths intersubband quantum dot light emitters are also presented.

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