scholarly journals Spectroscopic evidence of tunnel coupling between CdTe quantum wells in the CdTe/ZnTe heterostructures

2021 ◽  
Vol 2103 (1) ◽  
pp. 012102
Author(s):  
V Agekyan ◽  
N Filosofov ◽  
G Karczewski ◽  
A Serov ◽  
I Shtrom ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Atomic Layer ◽  
Pump Intensity ◽  
Excitation Intensity ◽  
Charge Carriers ◽  
Atomic Layer Epitaxy ◽  
Double Quantum ◽  
Excitation Wavelength ◽  
Carrier Relaxation ◽  
Tunnel Coupling

Abstract The photoluminescence (PL) spectra of CdTe/ZnTe double quantum wells (QWs) are studied on a series of samples containing two CdTe layers with nominal thicknesses of 2 and 4 monolayers (ML) in the ZnTe matrix. The QWs were grown in atomic-layer epitaxy and separated by ZnTe spacers with the thicknesses dsp =40−160 ML. The dependences of the relative intensity of shallow QW1 and deep QW2 PL bands (I1 and I2 , respectively) on the pump intensity (J) when excited by the lasers with different radiation wavelengths are investigated. It is found that in the sample with dsp=40 ML, the ratio Y(J)=I1/I2 depends on J and the shape of the Y(J) dependency changes with the excitation wavelength. In the samples with dsp > 70 ML Y(J) also changes with the excitation intensity J, but the shape of this dependence is the same for various excitation wavelengths. It is concluded that the energy relaxation in these samples is influenced not only by the tunneling of charge carriers from QW1 to QW2, but also by carrier relaxation at the nonradiative centers, for which the recombination rate is different for shallow and deep QWs.

Exciton Spectra and Energy Transfer in CdTe/ZnTe Double Quantum Wells Grown by Atomic-Layer Epitaxy

2019 ◽  
Vol 53 (16) ◽  
pp. 2060-2063 ◽  
Author(s):  
V. Agekyan ◽  
M. Chukeev ◽  
G. Karczewski ◽  
A. Serov ◽  
N. Filosofov ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Quantum Wells ◽  
Atomic Layer ◽  
Atomic Layer Epitaxy ◽  
Double Quantum

scholarly journals Fabricación y caracterización de diodos emisores de luz con emisión en la región verde azul

2017 ◽  
Vol 15 (19) ◽  
pp. 337
Author(s):  
Juan Carlos Salcedo Reyes
Keyword(s):  
Quantum Wells ◽  
Atomic Layer ◽  
Atomic Layer Epitaxy ◽  
Sobre Todo

El pasado 7 de octubre de 2014 se anunció, por parte del correspondiente comité, que el premio Nobel de Física 2014 se les concedió a los japoneses Isamu Akasaki, Hiroshi Amano y Shuji Nakamura por la invención de los diodos emisores de luz (LED, por sus siglas en inglés) con emisión en la región verde-azul del espectro visible (Nakamura, Mukai & Senoh, 1991). La importancia de este invento está relacionada tanto con las potenciales aplicaciones de los LED azules como fuente de luz eficiente y ecológica, como en el desarrollo de los llamados sistemas cuánticos. Es así como actualmente el desarrollo de dispositivos electrónicos y opto-electrónicos, cuya región activa está constituida por estructuras cuánticas, está fuertemente modulado por la capacidad de fabricar dichas estructuras con una alta calidad cristalina, un alto control de la composición química y, sobre todo, con gran reproducibilidad. En este sentido, las técnicas de crecimiento epitaxial constituyen la piedra angular en el desarrollo tecnológico que supone la nano-electrónica. En este trabajo se plantean, en general, los diferentes procesos químicos y físicos que tienen lugar durante un crecimiento por Epitaxia de Capas Atómicas (Atomic Layer Epitaxy, ALE) de pozos cuánticos ultra-delgados (Ultra-Thin Quantum Wells, UTQW) de ZnXCd1-X.Se y se estudian, en particular, la cinética del proceso de adsorción de Zn dentro de la estructura cristalina en términos de una ecuación de reacción de primer orden que define la composición de la estructura en función de la temperatura del sustrato (Ts) y del flujo de átomos de zinc. Se obtienen los valores para la energía de activación, el factor pre-exponencial y la constante de adsorción de Zn. La composición química de los UTQW es uno de los parámetros más importantes para el diseño de estructuras cuánticas, ya que define la energía de emisión en potenciales aplicaciones opto-electrónicas y, en particular, en el desarrollo de LED azules y UV.

Tunnel coupling in asymmetric semimagnetic double quantum wells

2008 ◽  
Vol 245 (1) ◽  
pp. 70-76 ◽  
Author(s):  
S. V. Zaitsev ◽  
M. K. Welsch ◽  
A. Forchel ◽  
G. Bacher
Keyword(s):  
Quantum Wells ◽  
Double Quantum ◽  
Tunnel Coupling

The Growth of AIGaAs/GaAs Heterostructures By Atomic Layer Epitaxy

1987 ◽  
Vol 102 ◽  
Author(s):  
S. P. Denbaars ◽  
A. Hariz ◽  
C. Beyler ◽  
B. Y. Maa ◽  
Q. Chen ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Metalorganic Chemical Vapor Deposition ◽  
Chemical Vapor ◽  
Active Regions ◽  
Atomic Layer ◽  
Atomic Layer Epitaxy ◽  
High Quality ◽  
Monolayer Growth ◽  
Low Threshold ◽  
Kinetics Of

ABSTRACTThe kinetics of atomic layer epitaxy (ALE) of GaAs utilizing trimethylgallium and arsine are described. The results show that saturated monolayer growth can be achieved-in the temperature range 445°C -485°C and that high quality materials can be grown.. Hybrid A1GaAs/GaAs heterostructures have been grown utilizing ALE for the active regions and conventional metalorganic chemical vapor deposition (MOCVD) for the confining regions that yield high quality quantum wells and low threshold quantum well lasers.

On the radiative recombination and tunneling of charge carriers in SiGe/Si heterostructures with double quantum wells

2016 ◽  
Vol 50 (12) ◽  
pp. 1604-1608
Author(s):  
A. N. Yablonsky ◽  
R. Kh. Zhukavin ◽  
N. A. Bekin ◽  
A. V. Novikov ◽  
D. V. Yurasov ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Radiative Recombination ◽  
Charge Carriers ◽  
Double Quantum

Collective excitations in double quantum wells with strong tunnel coupling

JETP Letters ◽  
2004 ◽  
Vol 79 (1) ◽  
pp. 48-52
Author(s):  
S. V. Tovstonog ◽  
L. V. Kulik ◽  
V. E. Kirpichev ◽  
I. V. Kukushkin ◽  
W. Dietsche ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Collective Excitations ◽  
Double Quantum ◽  
Tunnel Coupling

OPTICAL PROPERTIES OF CdTe/ZnTe ULTRATHIN QUANTUM WELLS GROWN BY ATOMIC LAYER EPITAXY

2002 ◽  
Vol 09 (05n06) ◽  
pp. 1667-1670 ◽  
Author(s):  
M. GARCÍA-ROCHA ◽  
I. HERNÁNDEZ-CALDERÓN
Keyword(s):  
Optical Properties ◽  
Low Temperature ◽  
Quantum Wells ◽  
Gaas Substrate ◽  
Room Temperature ◽  
Diffusion Length ◽  
Substrate Surface ◽  
Atomic Layer ◽  
Atomic Layer Epitaxy ◽  
Low Temperature Photoluminescence

Ultrathin quantum wells (UTQWs) of CdTe within ZnTe barriers were successfully grown by atomic layer epitaxy (ALE) on GaAs(001) substrates. ALE growth of CdTe was performed by alternate exposure of the substrate surface to individual fluxes of Cd and Te. Two different samples with 2-monolayer (ML) (substrate temperature Ts= 270° C ) and 4 ML (Ts = 290° C ) CdTe QWs were grown. Low temperature photoluminescence (PL) experiments exhibited intense and sharp peaks associated to the 2 ML QWs at 2.26 eV. In the case of the nominally 4-ML-thick QW the PL spectrum presented an intense peak around 2.13 eV and two weak features around 2.04 and 1.91 eV. The first peak is attributed to ~ 3 ML QW and the second one to ~ 4 ML QW. The dominance of the 3 ML peak is mainly attributed to Cd loss in the QW due to its substitution by Zn atoms. Due to a high diffusion length of the photogenerated carriers in the barriers, quite weak signals from the ZnTe barriers were observed in both cases. Room temperature (RT) photoreflectance (PR) spectra showed contributions from the CdTe UTQWs, the ZnTe barriers, and the GaAs substrate.

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