Optical Properties of Heavily Doped n-type CdSe Quantum Dots for Intersubband Device Applications

2006 ◽  
Vol 959 ◽  
Author(s):  
Shengkun Zhang ◽  
Xuecong Zhou ◽  
Aidong Shen ◽  
Wubao Wang ◽  
Robert Alfano ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Quantum Wells ◽  
Ir Absorption ◽  
Cdse Quantum Dots ◽  
Nonradiative Recombination ◽  
Time Resolved ◽  
Luminescence Efficiency ◽  
Decay Times ◽  
Heavily Doped

ABSTRACTIn this research, interband and intersubband optical properties of heavily doped n-type CdSe quantum dots were investigated by temperature dependent photoluminescence (PL) spectroscopy, picosecond time-resolved PL spectroscopy and Fourier transform infrared (FTIR) spectroscopy. Two doped and one undoped CdSe quantum dot samples with multiple QD layers were grown over ZnCdMgSe barrier layers on InP (001) substrate by molecular beam epitaxy. Heavy doping leads to decreasing of activation energy of nonradiative recombination centers, however, does not affect the luminescence efficiency of doped quantum wells. Time resolved PL experiments show that the PL decay times of the doped samples have weak dependence on well width and are much longer than that of the undoped sample. The two doped CdSe QD samples show strong Intersubband IR absorption that peaked at 2.54 μm, 2.69 μm and 3.51 μm. The ISB absorption is found to be strongly polarization dependent due to the large size of the QDs.

Optical Properties of Zn0.46Cd0.54Se/Zn0.24Cd0.25Mg0.51Se Multiple Quantum Wells for Infrared Photodetector Applications

2006 ◽  
Vol 952 ◽  
Author(s):  
Xuecong Zhou ◽  
Shengkun Zhang ◽  
Hong Lu ◽  
Aidong Shen ◽  
Wubao Wang ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Quantum Cascade Lasers ◽  
Multiple Quantum Wells ◽  
Multiple Quantum ◽  
Infrared Photodetector ◽  
Temperature Dependent ◽  
Time Resolved ◽  
Mid Infrared ◽  
Luminescence Efficiency ◽  
Decay Times

ABSTRACTRecently, lattice-matched Zn0.46Cd0.54Se/ZnCdMgSe multiple-quantum-wells (MQWs) have been recognized as very promising materials to fabricate intersubband (ISB) devices such as quantum cascade lasers and mid-infrared photoconductors. These structures have important applications in biological and chemical detections. The ISB transition covers a wide mid-infrared wavelength range from 1.3 μm to a few tens of μm.In this work, two heavily doped n-Zn0.46Cd0.54Se/Zn0.24Cd0.25Mg0.51Se MQW structures have been grown on InP (001) substrate by molecular beam epitaxy. Temperature dependent steady-state photoluminescence (SSPL), temperature dependent time- resolved photoluminescence (TRPL), and Fourier transform infrared spectroscopy (FTIR) were performed to characterize their interband and ISB properties. These two MQW samples have similar structures except different well widths and different number of periods. The integrated SSPL intensities and the PL decay times of the MQWs were measured as functions of temperature in the range from 77 K to 290 K. The luminescence efficiency of the sample with 28 Å well width is larger than that of the sample with 42 Å well width although both samples exhibit similar temperature dependence of PL intensity. Time-resolved PL measurements show that the PL decay times of both samples decrease with increasing temperature. From 77 K to 290 K, the decay time of the sample with 28 Å well width is in the range of 440 ps ∼ 120 ps and is much longer than that of the sample with 42 Å well width, which is in the range of 65 ps ∼ 25 ps. Strong non-radiative recombinations dominate the luminescence behavior of the wider MQWs. Intersubband absorption spectra of the samples were measured by FTIR and show peak absorption at wavelengths of 3.99 μm and 5.35 μm for the MQWs with well widths of 28 Å and 42 Å, respectively, falling within the 3-5 Åm range, which is of great interest for the infrared photodetector applications.

scholarly journals Investigation of Micromorphology and Carrier Recombination Dynamics for InGaN/GaN Multi-Quantum Dots Grown by Molecular Beam Epitaxy

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1312
Author(s):  
Xue Zhang ◽  
Wenxian Yang ◽  
Zhiwei Xing ◽  
Haibing Qiu ◽  
Ying Gu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Light Emitting Diode ◽  
Temperature Stability ◽  
Nonradiative Recombination ◽  
Uniform Size ◽  
Time Resolved ◽  
Decay Times ◽  
Increasing Temperature

InGaN quantum dots (QDs) are promising candidates for GaN-based all-visible optoelectronic devices such as micro light-emitting diode and laser. In this study, self-assembled InGaN/GaN multi-quantum dots (MQDs) have been grown by plasma-assisted molecular beam epitaxy on c-plane GaN-on-sapphire template. A high density of over 3.8 × 1010 cm−2 is achieved and InGaN QDs exhibit a relatively uniform size distribution and good dispersity. Strong localization effect in as-grown InGaN QDs has been evidenced by temperature-dependent photoluminescence (PL). The variation of peak energy is as small as 35 meV with increasing temperature from 10 K to 300 K, implying excellent temperature stability of emission wavelength for InGaN MQDs. Moreover, the radiative and nonradiative recombination times were calculated by time-resolved PL (TRPL) measurements, and the temperature dependence of PL decay times reveal that radiative recombination dominates the recombination process due to the low dislocation density of QDs structure.

scholarly journals Laser-induced fluorescence measurements on CdSe quantum dots

2010 ◽  
Vol 4 (1) ◽  
pp. 33-38 ◽  
Author(s):  
Zoltan Győri ◽  
Dávid Tátrai ◽  
Ferenc Sarlós ◽  
Gábor Szabó ◽  
Ákos Kukovecz ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Laser System ◽  
Laser Induced Fluorescence ◽  
Growth Time ◽  
Single Shot ◽  
Cdse Quantum Dots ◽  
Time Resolved ◽  
Fluorescence Measurements ◽  
Decay Times ◽  
Growth Method

In this paper, we report on photoluminescence decay measurements on CdSe quantum dots (QDs) as a function of size in the diameter range of 2.1 to 3.5 nm. The nanoparticles were synthesized by the kinetic growth method from CdO and elemental Se precursors. We studied the effects of growth time on the diameter, emission spectrum and the fluorescence lifetime of the synthesized QDs. The decay time measurements were performed using single shot time-resolved laser-induced fluorescence techniques using a Nd:YAG laser system. Two different decay times were measured on each CdSe sample, a fast one and a relatively slow one. The slow decay was found to be size dependent whereas the fast one was independent of the QD diameter. .

scholarly journals Intense Visible Luminescence in CdSe Quantum Dots by Efficiency Surface Passivation with H2O Molecules

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
Hyeoung Woo Park ◽  
Do-Hyung Kim
Keyword(s):  
Heat Treatment ◽  
Quantum Dots ◽  
Quantum Yield ◽  
Surface Passivation ◽  
Cdse Quantum Dots ◽  
Cdse Qds ◽  
Effect Of Water ◽  
Visible Luminescence ◽  
Luminescence Efficiency

We have investigated the effect of water (H2O) cooling and heat treatment on the luminescence efficiency of core CdSe quantum dots (QDs). The photoluminescence (PL) quantum yield of the CdSe QDs was enhanced up to ~85%, and some periodic bright points were observed in wide color ranges during the heat treatment of QDs mixed with H2O. The PL enhancement of QDs could be attributed to the recovery of QDs surface traps by unreacted ligands confined within the hydrophilic H2O molecule containers.

Influence of Resonant Excitation and Carrier Lifetime on the Optical Properties of Coupled CdSe Quantum Dots

2008 ◽  
Vol 53 (1) ◽  
pp. 106-109 ◽  
Author(s):  
Eunsoon Oh ◽  
Dong Gi Choi ◽  
Jung Hyun Park ◽  
Tae Kyu Lee ◽  
Sanghoon Lee ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Carrier Lifetime ◽  
Resonant Excitation ◽  
Cdse Quantum Dots

Multivariate optimization of optical properties of CdSe quantum dots obtained by a facile one-pot aqueous synthesis

2019 ◽  
Vol 6 (6) ◽  
pp. 1350-1360 ◽  
Author(s):  
Isabelle Moraes Amorim Viegas ◽  
Beate Saegesser Santos ◽  
Adriana Fontes ◽  
Giovannia Araujo de Lima Pereira ◽  
Claudete Fernandes Pereira
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Cdse Quantum Dots ◽  
Multivariate Optimization ◽  
High Quality ◽  
One Pot ◽  
Aqueous Synthesis ◽  
Synthesis Procedure

Four parameters are simultaneously optimized to provide a simple, fast and reproducible synthesis procedure to obtain high-quality CdSe quantum dots.

scholarly journals Comparison Study of Structural and Optical Properties of InxGa1−xN/GaN Quantum Wells with Different In Compositions

2000 ◽  
Vol 5 (S1) ◽  
pp. 977-983
Author(s):  
Yong-Hwan Kwon ◽  
G. H. Gainer ◽  
S. Bidnyk ◽  
Y. H. Cho ◽  
J. J. Song ◽  
...  
Keyword(s):  
Optical Properties ◽  
Quantum Wells ◽  
Chemical Vapor ◽  
Multiple Quantum ◽  
Nonradiative Recombination ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
Recombination Rates ◽  
Satellite Peak ◽  
Interface Quality

The effect of In on the structural and optical properties of InxGa1−xN/GaN multiple quantum wells (MQWs) was investigated. These were five-period MQWs grown on sapphire by metalorganic chemical vapor deposition. Increasing the In composition caused broadening of the high-resolution x-ray diffraction superlattice satellite peak and the photoluminescence-excitation bandedge. This indicates that the higher In content degrades the interface quality because of nonuniform In incorporation into the GaN layer. However, the samples with higher In compositions have lower room temperature (RT) stimulated (SE) threshold densities and lower nonradiative recombination rates. The lower RT SE threshold densities of the higher In samples show that the suppression of nonradiative recombination by In overcomes the drawback of greater interface imperfection.

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