scholarly journals Low-Cost Synthesis of Silicon Quantum Dots with Near-Unity Internal Quantum Efficiency

2021 ◽  
pp. 8909-8916
Author(s):  
Jingjian Zhou ◽  
Jing Huang ◽  
Huai Chen ◽  
Archana Samanta ◽  
Jan Linnros ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Efficiency ◽  
Internal Quantum Efficiency ◽  
Low Cost ◽  
Silicon Quantum Dots

Low Cost Fabrication of Blue Luminescent Silicon Quantum Dots Using Photo-Induced Chemical Etching

2016 ◽  
Vol 8 (1) ◽  
pp. 86-89 ◽  
Author(s):  
Young-In Lee ◽  
Bum-Sung Kim ◽  
Soyeong Joo ◽  
Woo-Byoung Kim
Keyword(s):  
Quantum Dots ◽  
Chemical Etching ◽  
Low Cost ◽  
Silicon Quantum Dots

scholarly journals UVB LEDs Grown by Molecular Beam Epitaxy Using AlGaN Quantum Dots

Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1097
Author(s):  
Julien Brault ◽  
Mohamed Al Khalfioui ◽  
Samuel Matta ◽  
Thi Huong Ngo ◽  
Sébastien Chenot ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Molecular Beam Epitaxy ◽  
Quantum Efficiency ◽  
Molecular Beam ◽  
Internal Quantum Efficiency ◽  
Ultra Violet ◽  
Time Resolved ◽  
Light Emitting ◽  
Commercial Markets ◽  
Nm Range

AlGaN based light emitting diodes (LEDs) will play a key role for the development of applications in the ultra-violet (UV). In the UVB region (280–320 nm), phototherapy and plant lighting are among the targeted uses. However, UVB LED performances still need to be improved to reach commercial markets. In particular, the design and the fabrication process of the active region are central elements that affect the LED internal quantum efficiency (IQE). We propose the use of nanometer-sized epitaxial islands (i.e., so called quantum dots (QDs)) to enhance the carrier localization and improve the IQE of molecular beam epitaxy (MBE) grown UVB LEDs using sapphire substrates with thin sub-µm AlN templates. Taking advantage of the epitaxial stress, AlGaN QDs with nanometer-sized (≤10 nm) lateral and vertical dimensions have been grown by MBE. The IQE of the QDs has been deduced from temperature dependent and time resolved photoluminescence measurements. Room temperature IQE values around 5 to 10% have been found in the 290–320 nm range. QD-based UVB LEDs were then fabricated and characterized by electrical and electroluminescence measurements. On-wafer measurements showed optical powers up to 0.25 mW with external quantum efficiency (EQE) values around 0.1% in the 305–320 nm range.

Enhancement of carrier localization effect and internal quantum efficiency through In-rich InGaN quantum dots

2018 ◽  
Vol 113 ◽  
pp. 497-501 ◽  
Author(s):  
Jianjie Liu ◽  
Zhigang Jia ◽  
Shufang Ma ◽  
Hailiang Dong ◽  
Guangmei Zhai ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Efficiency ◽  
Internal Quantum Efficiency ◽  
Carrier Localization ◽  
Localization Effect

Synthesis of Silicon Quantum Dots Showing High Quantum Efficiency

2014 ◽  
Vol 14 (8) ◽  
pp. 5868-5872 ◽  
Author(s):  
Bomin Cho ◽  
Sangsoo Baek ◽  
Hee-Gweon Woo ◽  
Honglae Sohn
Keyword(s):  
Quantum Dots ◽  
Quantum Efficiency ◽  
Silicon Quantum Dots ◽  
High Quantum Efficiency ◽  
High Quantum

Low‐Cost Water Soluble Silicon Quantum Dots and Biocompatible Fluorescent Composite Films

2021 ◽  
pp. 2100173
Author(s):  
Guitao Du ◽  
Guoqian Li ◽  
Shibo Qiu ◽  
Linghong Liu ◽  
Yuewei Zheng ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Low Cost ◽  
Composite Films ◽  
Water Soluble ◽  
Silicon Quantum Dots ◽  
Soluble Silicon

Germanium-Silicon Quantum Dots Produced by Pulsed Laser Deposition for Photovoltaic Applications

2011 ◽  
Vol 383-390 ◽  
pp. 6270-6276 ◽  
Author(s):  
Li Hao Han ◽  
Jing Wang ◽  
Ren Rong Liang
Keyword(s):  
Quantum Dots ◽  
Pulsed Laser Deposition ◽  
Quartz Substrate ◽  
Low Cost ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Silicon Quantum Dots ◽  
Photovoltaic Application ◽  
Photovoltaic Applications ◽  
Germanium Silicon

Quantum dots applied in solar cells will be of great importance to enhance the quantum tunneling efficiency and improve the photogenerated current transport. In this study, a new easy-to-operate technology was developed to fabricate germanium-silicon quantum dots in a SiOx matrix. The quantum dots were formed by first deposited germanium-rich SiO on quartz substrate using pulsed laser deposition technique and then annealed under a comparatively high temperature. We have demonstrated a stable and low-cost fabrication process which is much cheaper than the epitaxy method to provide for the fabrication of high density germanium-silicon quantum dots. Quantum dots with diameters of 3~4 nm embedded in the amorphous SiOx layer were clearly observed. The morphological features of the thin film were characterized. The optical properties were performed by Raman spectroscopy, photoluminescence spectrum and XRD test respectively to verify the crystallization of quantum dots in the SiOx matrix. Reflectance spectrum displayed a high light absorption rate in a spectra region from 300 nm to 1200 nm, evidencing that germanium-silicon quantum dots have promising features to be used as absorber for photovoltaic application.

scholarly journals Studies on Carrier Recombination in GaN/AlN Quantum Dots in Nanowires with a Core–Shell Structure

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2299
Author(s):  
Jun Deng ◽  
Zhibiao Hao ◽  
Lai Wang ◽  
Jiadong Yu ◽  
Jian Wang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Efficiency ◽  
Shell Structure ◽  
Internal Quantum Efficiency ◽  
Systematic Research ◽  
Core Shell ◽  
Band Bending ◽  
Recombination Mechanism ◽  
Carrier Recombination ◽  
Core Shell Structure

GaN quantum dots embedded in nanowires have attracted much attention due to their superior optical properties. However, due to the large surface-to-volume ratio of the nanowire, the impacts of surface states are the primary issue responsible for the degradation of internal quantum efficiency (IQE) in heterostructured dot-in-nanowires. In this paper, we investigate the carrier recombination mechanism of GaN/AlN dot-in-nanowires with an in situ grown AlN shell structure. Ultraviolet photoelectron spectroscopy (UPS) measurements were performed to describe the band bending effect on samples with different shell thicknesses. Temperature-dependent photoluminescence (TDPL) data support that increasing the AlN shell thickness is an efficient way to improve internal quantum efficiency. Detailed carrier dynamics was analyzed and combined with time-resolved photoluminescence (TRPL). The experimental data are consistent with our physical model that the AlN shell can effectively flatten the band bending near the surface and isolate the surface non-radiative recombination center. Our systematic research on GaN/AlN quantum dots in nanowires with a core–shell structure may significantly advance the development of a broad range of nanowire-based optoelectronic devices.

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