Intraband Absorption in Ge/Si Self-Assembled Quantum Dots

1999 ◽  
Vol 571 ◽  
Author(s):  
P. Boucaud ◽  
V. Le Thanh ◽  
S. Sauvage ◽  
T. Brunhes ◽  
F. Fortuna ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Cross Section ◽  
Absorption Cross Section ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Ultra High Vacuum ◽  
Absorption Cross ◽  
Mid Infrared ◽  
Intraband Absorption ◽  
Self Assembled

ABSTRACTMid-infrared intraband absorption in Ge/Si self-assembled quantum dots is reported. The self-assembled quantum dots are grown by ultra-high-vacuum chemical vapor deposition. The intraband absorption is observed using a photoinduced absorption technique. The mid-infrared absorption, which is in-plane polarized, is maximum around 300 meV. The absorption is attributed to a quantum dot hole transition between bound and continuum states. The absorption cross section is deduced from the saturation of the photoinduced intraband absorption. An inplane absorption cross section as large as 2 × 10−13 cm2 is measured for one dot plane.

Challenge to 200 mm 3C-SiC Wafers Using SOI

2005 ◽  
Vol 483-485 ◽  
pp. 205-208 ◽  
Author(s):  
Motoi Nakao ◽  
Hirofumi Iikawa ◽  
Katsutoshi Izumi ◽  
Takashi Yokoyama ◽  
Sumio Kobayashi
Keyword(s):  
Cross Section ◽  
Vapor Deposition ◽  
Seed Layer ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Ultra High Vacuum ◽  
Average Thickness ◽  
Entire Region ◽  
Transmission Electron ◽  
Good Crystallinity

200 mm wafer with 3C-SiC/SiO2/Si structure has been fabricated using 200 mm siliconon- insulator (SOI) wafer. A top Si layer of 200 mm SOI wafer was thinned down to approximately 5 nm by sacrificial oxidization, and the ultrathin top Si layer was metamorphosed into a 3C-SiC seed layer using a carbonization process. Afterward, an epitaxial SiC layer was grown on the SiC seed layer with ultra-high vacuum chemical vapor deposition. A cross-section transmission electron microscope indicated that a 3C-SiC seed layer was formed directly on the buried oxide layer of 200 mm wafer. The epitaxial SiC layer with an average thickness of approximately 100 nm on the seed was recognized over the entire region of the wafer, although thickness uniformity of the epitaxial SiC layer was not as good as that of SiC seed layer. A transmission electron diffraction image of the epitaxial SiC layer showed a monocrystalline 3C-SiC(100) layer with good crystallinity. These results indicate that our method enables to realize 200 mm SiC wafers.

On the determination of absorption cross section of colloidal lead halide perovskite quantum dots

2019 ◽  
Vol 151 (15) ◽  
pp. 154706 ◽  
Author(s):  
Joseph Puthenpurayil ◽  
Oscar Hsu-Cheng Cheng ◽  
Tian Qiao ◽  
Daniel Rossi ◽  
Dong Hee Son
Keyword(s):  
Quantum Dots ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Absorption Cross ◽  
Perovskite Quantum Dots ◽  
Halide Perovskite ◽  
Colloidal Lead ◽  
Lead Halide

Investigation of Epitaxial Overgrowth on Germanium Quantum Dots

2001 ◽  
Vol 676 ◽  
Author(s):  
David W. Greve ◽  
Qian Zhao
Keyword(s):  
Quantum Dots ◽  
Vapor Deposition ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Ultra High Vacuum ◽  
Reciprocal Space Mapping ◽  
Silicon Epitaxial Layer ◽  
Germanium Quantum Dots ◽  
Uniform Quantum

ABSTRACTWe report on the characterization of germanium quantum dots grown on silicon (001) substrates by ultra-high vacuum chemical vapor deposition (UHV/CVD). In many applications small and uniform quantum dots are required which must be overgrown by a silicon epitaxial layer. We report here on the effect of carbon predeposition from methylsilane on the dot size and uniformity. In addition, we use reciprocal space mapping to evaluate the qualityof epitaxial layers which overgrow the quantum dots. The results show some differences from previous reports on MBE-grown dots.

Optical absorption cross section of quantum dots

2004 ◽  
Vol 16 (35) ◽  
pp. S3749-S3756 ◽  
Author(s):  
S W Osborne ◽  
P Blood ◽  
P M Smowton ◽  
Y C Xin ◽  
A Stintz ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Absorption ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Absorption Cross

Harnessing molecular photon upconversion at sub-solar irradiance using dual sensitized self-assembled trilayers

2017 ◽  
Vol 5 (23) ◽  
pp. 11652-11660 ◽  
Author(s):  
Tristan Dilbeck ◽  
Sean P. Hill ◽  
Kenneth Hanson
Keyword(s):  
Metal Oxide ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Solar Irradiance ◽  
Oxide Surfaces ◽  
Absorption Cross ◽  
Generation Efficiency ◽  
Metal Oxide Surfaces ◽  
Photocurrent Generation ◽  
Self Assembled

Self-assembled trilayers on metal oxide surfaces are used to increase absorption cross section and photocurrent generation efficiency via triplet–triplet annihilation.

Absorption Cross-Section and Related Optical Properties of Colloidal InAs Quantum Dots

2005 ◽  
Vol 109 (15) ◽  
pp. 7084-7087 ◽  
Author(s):  
Pingrong Yu ◽  
Matthew C. Beard ◽  
Randy J. Ellingson ◽  
Suzanne Ferrere ◽  
Calvin Curtis ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Absorption Cross ◽  
Inas Quantum Dots

Self-assembled Ge quantum dots on SiC substrates grown by UHV-CVD

2002 ◽  
Vol 742 ◽  
Author(s):  
C. Calmes ◽  
V. Le ◽  
D. Bouchier ◽  
S. E. Saddow ◽  
V. Yam ◽  
...  
Keyword(s):  
Quantum Dots ◽  
High Vacuum ◽  
Chemical Vapor ◽  
High Energy ◽  
Surface Cleaning ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
First Results ◽  
Ge Quantum Dots

AbstractWe report our first results using a ultra high vacuum chemical vapor deposition (UHV-CVD) system to form Ge quantum dots on off-axis SiC substrates. Pure SiH4 and hydrogen-diluted GeH4 were used as gas precursors. The SiC substrates were chemically cleaned using the modified RCA process and the SiO2 layer was removed in-situ under a low SiH4 flow rate at a temperature between 1030°C and 1080°C. The Ge quantum dots were grown at a temperature of 750°C. In-situ reflection high-energy electron diffraction (RHEED) was used to monitor the surface cleaning and the Ge quantum dot growth. Ex-situ scanning electron microscope and atomic force microscopy were used to confirm the presence of Ge dots. The observed dots are smaller (350 Å width and 100 Å height) than similar Ge dots grown on Si.

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