Optical Characterization of InGaAs/InP Quantum Wires and Dots

1993 ◽  
Vol 324 ◽  
Author(s):  
S.Q. Gu ◽  
E. Reuter ◽  
Q. Xu ◽  
H. Chang ◽  
R. Panepucci ◽  
...  
Keyword(s):  
Electron Beam Lithography ◽  
Quantum Confinement ◽  
Quantum Wires ◽  
Blue Shift ◽  
Optical Characterization ◽  
Excitation Intensity ◽  
Resolution Electron ◽  
Quantum Well Wires ◽  
Peak Emission

AbstractHigh resolution electron beam lithography and reactive ion etching in methane-hydrogen (CH4/H2) plasmas have been used to fabricate InGaAs/InP open quantum well wires (QWW) with widths ranging from 200 to 40 nm and quantum dots (QD) with diameters ranging from 600 to 100 nm. Low temperature photoluminescence (PL) spectra were investigated in these nanostructures as a function of excitation intensity, wire width, and dot diameter. The peak emission of the dry-etched 40 nm wires is shifted to higher energies by about 2 meV as compared to 100 nm wires. This “open wire” result is consistent with results reported for buried InGaAs/InP wires of the same width. The blue-shift of the PL peak reaches 10 meV in QDs as their diameters decrease to 100 nm. The magnitude of the observed blue shift in the QDs is larger than the blue-shift predicted on the basis of quantum confinement for the same size dots.

Fabrication of Quantum Wires by Wet Etching Techniques

1993 ◽  
Vol 325 ◽  
Author(s):  
H. W. Yang ◽  
S. F. Horng ◽  
H. L. Hwang
Keyword(s):  
Quantum Well ◽  
Electron Beam Lithography ◽  
Quantum Confinement ◽  
Chemical Etching ◽  
Quantum Wires ◽  
Blue Shift ◽  
Wet Etching ◽  
Photoluminescence Excitation ◽  
Wet Chemical ◽  
Wet Chemical Etching

AbstractQuantum Wires Structures Were Fabricated By Patterning Quantum Well Samples With Electron Beam Lithography And Various Wet Chemical Etching Procedures. Wire Structures With 800Å Wire Width Were Achieved By Wet Etching In Nh4Oh / H2O2 / H2O (20:7:973). These Samples Were Characterized By Scanning Electron Microscopy (Sem), Photoluminescence (Pl), And Polarization-Dependent Photoluminescence Excitation (Ple) Measurements. The Pl Spectra Show Significantly Strongpr Peaks Than That Taken From An En-Etched Quantum Well Sample. A Wire Width Of 400Å Was Estimated From The Blue Shift Of Pl Peaks. A 22% Anisotropy Was Observed From Polarization-Dependent Ple Spectra, Further Corroborating The Existence Of Two-Dimensional Quantum Confinement.

Optical Properties of InGaAs/InP Quantum Wires Defined by High Voltage Electron Beam Lithography at 200 kV

1992 ◽  
Vol 283 ◽  
Author(s):  
P. Ils ◽  
M. Michel ◽  
A. Forchel ◽  
I. Gyuro ◽  
P. Speier ◽  
...  
Keyword(s):  
Electron Beam ◽  
Electron Beam Lithography ◽  
Quantum Wires ◽  
Optical Emission ◽  
Blue Shift ◽  
Ingaas Layer ◽  
Lithography Process ◽  
Voltage Electron ◽  
Side Walls ◽  
Wet Chemical

ABSTRACTWe have fabricated and analyzed high quality InGaAs/InP quantum wires by electron beam lithography and wet chemical etching. In order to optimize the shape of the wet-etched wires different wire orientations were investigated. As results of the lithography process we obtain wire masks with widths down to 15 nm and etched wires with widths of the InGaAs layer of 18 nm.The wires were studied optically by means of photoluminescence spectroscopy. In contrast to dry etched wire structures the wet chemically etched wires show strong optical emission even for geometrical widths less than 25 nm. The weak decrease of the quantum efficiency with decreasing wire width indicates that there are no dead layers at the side walls of the wires, which is in contrast to previous studies on dry-etched structures. The photoluminescence energy of the InGaAs/InP wires is independent of the wire dimension down to widths of 50 nm. This indicates that a steep lateral potential in our structures is obtained due to the confinement by the semiconductor/vacuum transition at the etched surfaces. For wires with smaller widths an increasing blue shift of photoluminescence energy up to more than 30 meV is observed.

Optical Characterization of Buried Ingaas/GaAs Wires Overgrown by MBE

1993 ◽  
Vol 318 ◽  
Author(s):  
K. Pieger ◽  
J. Straka ◽  
Ch. Gréus ◽  
A. Forchel
Keyword(s):  
Surface Recombination ◽  
Optical Characterization ◽  
Gaas Layer ◽  
Photoluminescence Intensity ◽  
Temperature Growth ◽  
Resolution Electron ◽  
Wet Chemical ◽  
Wet Chemical Etching ◽  
Induced Defects

ABSTRACTWe have prepared buried InGaAs/GaAs wires by high resolution electron beam lithography, wet chemical etching and subsequent MBE overgrowth. Wires with lateral widths of less than 40nm have been realized.For optimized regrowth conditions such as growth temperature, growth rate, III/V ratio, and arsenic flux a smooth surface morphology of the 100nm thick overgrown (Al)GaAs layer is obtained.Etched only ultra narrow wires show a decrease of radiative recombination due to process induced defects and surface recombination at the open sidewalls. Optical investigations of narrow overgrown wires show a significant enhancement (up to two orders of magnitude) of the photoluminescence intensity. This is due to the disappearance of the open sidewalls and carrier capture from the overgrown barrier.From studies of the influence of the crystallographic orientation on the quantum efficiency we find, that <111>B surfaces of the <011> wires offer the best conditions for MBE overgrowth.

Optical characterization of selectively intermixed GaAs/GaAlAs quantum wires by Ga+masked implantation

1991 ◽  
Vol 70 (3) ◽  
pp. 1444-1450 ◽  
Author(s):  
C. Vieu ◽  
M. Schneider ◽  
D. Mailly ◽  
R. Planel ◽  
H. Launois ◽  
...  
Keyword(s):  
Quantum Wires ◽  
Optical Characterization

LP-MOVPE growth and optical characterization of GaInP/GaAs heterostructures: interfaces, quantum wells and quantum wires

1992 ◽  
Vol 124 (1-4) ◽  
pp. 199-206 ◽  
Author(s):  
F.E.G. Guimarães ◽  
B. Elsner ◽  
R. Westphalen ◽  
B. Spangenberg ◽  
H.J. Geelen ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Quantum Wires ◽  
Optical Characterization ◽  
Movpe Growth

MOVPE growth and optical characterization of InGaAsN T-shaped quantum wires lattice-matched to GaAs

2010 ◽  
Vol 207 (6) ◽  
pp. 1418-1420 ◽  
Author(s):  
Pawinee Klangtakai ◽  
Sakuntam Sanorpim ◽  
Ryuji Katayama ◽  
Kentaro Onabe
Keyword(s):  
Quantum Wires ◽  
Optical Characterization ◽  
Movpe Growth ◽  
Lattice Matched

scholarly journals Synthesis and characterization of Ag-chalcogenide nanoparticles for possible applications in photovoltaics

2018 ◽  
Vol 36 (3) ◽  
pp. 375-380 ◽  
Author(s):  
Subhash Chand ◽  
Pankaj Sharma
Keyword(s):  
Crystallite Size ◽  
Structural Parameters ◽  
Blue Shift ◽  
Optical Characterization ◽  
Molar Ratio ◽  
Synthesis And Characterization ◽  
Capping Agent ◽  
X Ray Diffraction ◽  
X Ray

AbstractBottom-up technique has been used to synthesize Ag-chalcogenide nanoparticles. This work reports on the synthesis of Ag2Se by varying the molar ratio of capping agent and pH of the solution. The synthesized nanoparticles have been characterized in terms of structural parameters using X-ray diffraction. By this technique, various parameters such as crystallite size, dislocation density and strain of the nanoparticles were calculated. The crystallite size decreased with the increase in pH of the solution. The optical characterization was carried out by UV-Vis-NIR spectrophotometer. With the decrease in the crystallite size, a blue shift in the absorption peak of the nanoparticles was observed. These properties are suitable for energy harvesting with the help of photovoltaics.

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