scholarly journals МОДЕЛИРОВАНИЕ И РАСЧЕТ СПЕКТРА ФОТОЛЮМИНЕСЦЕНЦИИ ГЕТЕРОСТРУКТУРЫ С КВАНТОВОЙ ЯМОЙ НА ПРИМЕРЕ ALGaAS/GaAS

2021 ◽  
Vol 6 (12(81)) ◽  
pp. 30-35
Author(s):  
З. Давыдова
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Semiconductor Layer ◽  
Optimal Composition ◽  
Photoluminescence Spectra ◽  
Frequency Range ◽  
Emission Frequency ◽  
Layer Width ◽  
Multilayer Heterostructures ◽  
Infrared Frequency Range

This research aims to improve the available means for characterizing the emission properties of quantum well heterostructures by modeling and calculating the absorption and photoluminescence spectra using the GaAs/AlGaAs heterostructure as an example. Research is conducted based on multilayer heterostructures and heterostructures with quantum wells to develop detectors and emitting elements in the infrared frequency range, pulsed solid-state generators in the millimeter and submillimeter-wave ranges. The study of radiating properties of heterostructures with a quantum well on A3B5 compounds has become widespread [1-3]. It is possible to control the heterostructure's emission frequency by selecting the optimal composition of the wideband semiconductor layer, the level and type of its doping, the doping region, and the quantum well layer width, which is of applied importance for the development of optoelectronic devices. Technologies for manufacturing such heterostructures are labor-intensive, time-consuming, and expensive processes, which contribute to developing methods for modeling and calculating the characteristic frequencies of radiation and absorption of radiation. Based on such calculations, radiating elements of the submicronic wavelength range can be developed based on heterostructures with a quantum well on the A3B5 type compounds. [4]

scholarly journals МОДЕЛИРОВАНИЕ И РАСЧЕТ СПЕКТРА ФОТОЛЮМИНЕСЦЕНЦИИ ГЕТЕРОСТРУКТУРЫ С КВАНТОВОЙ ЯМОЙ НА ПРИМЕРЕ ALGaAS/GaAS

2021 ◽  
Vol 6 (12(81)) ◽  
pp. 30-35
Author(s):  
З. Давыдова
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Semiconductor Layer ◽  
Optimal Composition ◽  
Photoluminescence Spectra ◽  
Frequency Range ◽  
Emission Frequency ◽  
Layer Width ◽  
Multilayer Heterostructures ◽  
Infrared Frequency Range

This research aims to improve the available means for characterizing the emission properties of quantum well heterostructures by modeling and calculating the absorption and photoluminescence spectra using the GaAs/AlGaAs heterostructure as an example. Research is conducted based on multilayer heterostructures and heterostructures with quantum wells to develop detectors and emitting elements in the infrared frequency range, pulsed solid-state generators in the millimeter and submillimeter-wave ranges. The study of radiating properties of heterostructures with a quantum well on A3B5 compounds has become widespread [1-3]. It is possible to control the heterostructure's emission frequency by selecting the optimal composition of the wideband semiconductor layer, the level and type of its doping, the doping region, and the quantum well layer width, which is of applied importance for the development of optoelectronic devices. Technologies for manufacturing such heterostructures are labor-intensive, time-consuming, and expensive processes, which contribute to developing methods for modeling and calculating the characteristic frequencies of radiation and absorption of radiation. Based on such calculations, radiating elements of the submicronic wavelength range can be developed based on heterostructures with a quantum well on the A3B5 type compounds. [4]

scholarly journals Photoluminescence measurements on GaN/AlGaN modulation doped quantum wells

1999 ◽  
Vol 4 (1) ◽  
Author(s):  
J. Dalfors ◽  
J. P. Bergman ◽  
P.O. Holtz ◽  
B. Monemar ◽  
H. Amano ◽  
...  
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Electron Gas ◽  
Energy Transition ◽  
Photoluminescence Spectra ◽  
Photoluminescence Decay ◽  
Fermi Edge ◽  
Decay Times ◽  
Piezoelectric Field ◽  
Good Agreement

Photoluminescence spectra were measured for 100 Å wurtzite GaN AlGaN modulation doped quantum wells. Three well-resolved peaks originate from the quantum well. The theoretically calculated confinement energies have been compared to the experimental energy positions and found to be in good agreement with the data, assuming that the piezoelectric field is largely screened by the electron gas. The highest energy transition may originate from the Fermi edge, consistent with the temperature dependence of the photoluminescence. Decay times for the different transitions indicate that the photoexcited holes are localized.

Transient photoluminescence spectra of GaAs/AlGaAs quantum wells, quantum well wires, and quantum well boxes

1990 ◽  
Vol 7 (6) ◽  
pp. 284-287 ◽  
Author(s):  
Cheng Wenqin ◽  
Huang Yi ◽  
Zhou Junming ◽  
Feng Wei ◽  
Wang Hezhou ◽  
...  
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Photoluminescence Spectra ◽  
Quantum Well Wires

scholarly journals Photoluminescence Spectra of MESFET and HEMT

1995 ◽  
Vol 17 (4) ◽  
pp. 207-225
Author(s):  
P. Conti
Keyword(s):  
Quantum Wells ◽  
Room Temperature ◽  
Photoluminescence Spectroscopy ◽  
Semiconductor Layer ◽  
Photoluminescence Spectra ◽  
Buried Interfaces ◽  
Semiconductor Quantum Wells ◽  
Reliability Assessments ◽  
Low Amplitude ◽  
Layer Composition

Photoluminescence spectroscopy has been employed in previous studies of semiconductor quantum wells and of buried interfaces in heterostructures. Nevertheless, the low amplitude of the signals collected, and the experimental difficulties, have limited the analyses to samples made on purpose.On the contrary, in this work, the analyses at room temperature and at 4 K of a commercial MESFET and of a commercial HEMT are presented. With the performed experiments, new informations about the composition of these components were achieved; in particular signals from deep levels and from the Cr states of the HEMT substrate were detected.After further studies on the shape of the spectra, the photoluminescence could probably be employed in reliability assessments to show the modifications in the semiconductor layer composition and in the shape of the heterostructure's surfaces of single devices.

Optical Properties of Pseudomorphic InxGa1−xAs Quantum Wells

1986 ◽  
Vol 77 ◽  
Author(s):  
N. G. Anderson ◽  
Y. C. Lo ◽  
R. M. Kolbas
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Excitation Intensity ◽  
Stimulated Emission ◽  
Luminescence Properties ◽  
Photoluminescence Spectra ◽  
Quantum Well Structures ◽  
Single Feature ◽  
Increasing Temperature ◽  
Confining Layers

ABSTRACTThe luminescence properties of MBE-grown pseudomorphic InxGa1−xAs—GaAs quantum-well structures are examined as a function of photoexcitation intensity and temperature. The structures examined consist of single In0.28Ga0.72As or (isolated) multiple In0.16Ga0.84As pseudomorphic wells sandwiched between thick, unstrained GaAs confining layers. Low-temperature photoluminescence spectra for these samples, which range in quantum-well thickness from 17 Å to 50 Å, consist of a single feature attributable to transitions associated with n = 1 electron and j = 3/2, Mj = 3/2 > - hole states. Spectral widths of these peaks are very narrow (7–11 meV), even for a heavily spike-doped sample (Si, ND ∼ 1018 spike-doped at well center). Emission intensities for the quantum-well structures are studied as a function of excitation intensity over the range 3 × 102 ≤ Pex ≤ 6 x 1O4 W/cm2, and one of the samples (x = 0.16, 50 Å undoped wells) prepared as a laser structure is shown to support stimulated emission at an excitation intensity < 104 W/cm2. The excellent luminescence properties of these structures are shown to degrade rapidly with increasing temperature, with radiative efficiencies dropping more than two orders of magnitude over the temperature range 20K – 180K. One possible explanation for this behavior is proposed.

Effect of Annealing on Strained InGaAs/GaAs Quantum Wells

1989 ◽  
Vol 160 ◽  
Author(s):  
Emil S. Koteles ◽  
B. Elman ◽  
P. Melman ◽  
C.A. Armiento
Keyword(s):  
Optical Properties ◽  
Quantum Well ◽  
Quantum Wells ◽  
Lattice Constant ◽  
Thermal Processing ◽  
Semiconductor Heterostructures ◽  
Photoluminescence Spectra ◽  
Barrier Layers ◽  
The Difference ◽  
Diffusion Of Vacancies

AbstractWe have demonstrated that shallow ion (75As+) implantation and rapid thermal annealing (RTA) of strained InGaAs/GaAs quantum well (QW) structures can modify the optical properties of these epitaxial semiconductor heterostructures in a spatially selective manner. After RTA, exciton QW energies, determined from peaks in the photoluminescence spectra, shifted significantly to higher values only in the implanted regions. The magnitudes of the shifts were dependent on QW widths, RTA temperatures, and implantation fluences. The shifts were interpreted as resulting from the modification of the shapes of the as-grown QWs from square (abrupt interfaces) to rounded (gradual interfaces) due to enhanced indium diffusion out of the well layers in irradiated areas as a consequence of the diffusion of vacancies generated near the surface by the implantation. The thermal processing had only a small effect on the strain present in the quantum well layers due to the difference in the lattice constant of the well and barrier layers.

Characterization of GaAs/AlGaAs quantum wells and quantum wires by chemical lattice imaging

1994 ◽  
Vol 52 ◽  
pp. 736-737
Author(s):  
A. Carlsson ◽  
J.-O. Malm ◽  
A. Gustafsson
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Quantum Wires ◽  
Vapour Phase ◽  
Quantitative Information ◽  
Lattice Imaging ◽  
Vapour Phase Epitaxy ◽  
Metalorganic Vapour Phase Epitaxy ◽  
High Resolution Images

In this study a quantum well/quantum wire (QW/QWR) structure grown on a grating of V-grooves has been characterized by a technique related to chemical lattice imaging. This technique makes it possible to extract quantitative information from high resolution images.The QW/QWR structure was grown on a GaAs substrate patterned with a grating of V-grooves. The growth rate was approximately three monolayers per second without growth interruption at the interfaces. On this substrate a barrier of nominally Al0.35 Ga0.65 As was deposited to a thickness of approximately 300 nm using metalorganic vapour phase epitaxy . On top of the Al0.35Ga0.65As barrier a 3.5 nm GaAs quantum well was deposited and to conclude the structure an additional approximate 300 nm Al0.35Ga0.65 As was deposited. The GaAs QW deposited in this manner turns out to be significantly thicker at the bottom of the grooves giving a QWR running along the grooves. During the growth of the barriers an approximately 30 nm wide Ga-rich region is formed at the bottom of the grooves giving a Ga-rich stripe extending from the bottom of each groove to the surface.

Characterisation of multilayer materials using a position-sensitive atom probe

1990 ◽  
Vol 48 (4) ◽  
pp. 624-625
Author(s):  
RAD Mackenzie ◽  
G D W Smith ◽  
A. Cerezo ◽  
J A Liddle ◽  
CRM Grovenor ◽  
...  
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Spatial Information ◽  
Chemical Vapour ◽  
Atom Probe ◽  
Organic Chemical ◽  
Growth Stages ◽  
Multiple Quantum ◽  
Quartz Wool ◽  
Position Sensitive

The position sensitive atom probe (POSAP), described briefly elsewhere in these proceedings, permits both chemical and spatial information in three dimensions to be recorded from a small volume of material. This technique is particularly applicable to situations where there are fine scale variations in composition present in the material under investigation. We report the application of the POSAP to the characterisation of semiconductor multiple quantum wells and metallic multilayers.The application of devices prepared from quantum well materials depends on the ability to accurately control both the quantum well composition and the quality of the interfaces between the well and barrier layers. A series of metal organic chemical vapour deposition (MOCVD) grown GaInAs-InP quantum wells were examined after being prepared under three different growth conditions. These samples were observed using the POSAP in order to study both the composition of the wells and the interface morphology. The first set of wells examined were prepared in a conventional reactor to which a quartz wool baffle had been added to promote gas intermixing. The effect of this was to hold a volume of gas within the chamber between growth stages, leading to a structure where the wells had a composition of GalnAsP lattice matched to the InP barriers, and where the interfaces were very indistinct. A POSAP image showing a well in this sample is shown in figure 1. The second set of wells were grown in the same reactor but with the quartz wool baffle removed. This set of wells were much better defined, as can be seen in figure 2, and the wells were much closer to the intended composition, but still with measurable levels of phosphorus. The final set of wells examined were prepared in a reactor where the design had the effect of minimizing the recirculating volume of gas. In this case there was again further improvement in the well quality. It also appears that the left hand side of the well in figure 2 is more abrupt than the right hand side, indicating that the switchover at this interface from barrier to well growth is more abrupt than the switchover at the other interface.

scholarly journals Asymmetric Ge/SiGe coupled quantum well modulators

Nanophotonics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1765-1773
Author(s):  
Yi Zhang ◽  
Jianfeng Gao ◽  
Senbiao Qin ◽  
Ming Cheng ◽  
Kang Wang ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Quantum Well ◽  
Quantum Wells ◽  
High Speed ◽  
Low Voltage ◽  
Extinction Ratio ◽  
High Frequency Response ◽  
Modulation Format ◽  
Silicon Photonic ◽  
Coupled Quantum Well

Abstract We design and demonstrate an asymmetric Ge/SiGe coupled quantum well (CQW) waveguide modulator for both intensity and phase modulation with a low bias voltage in silicon photonic integration. The asymmetric CQWs consisting of two quantum wells with different widths are employed as the active region to enhance the electro-optical characteristics of the device by controlling the coupling of the wave functions. The fabricated device can realize 5 dB extinction ratio at 1446 nm and 1.4 × 10−3 electrorefractive index variation at 1530 nm with the associated modulation efficiency V π L π of 0.055 V cm under 1 V reverse bias. The 3 dB bandwidth for high frequency response is 27 GHz under 1 V bias and the energy consumption per bit is less than 100 fJ/bit. The proposed device offers a pathway towards a low voltage, low energy consumption, high speed and compact modulator for silicon photonic integrated devices, as well as opens possibilities for achieving advanced modulation format in a more compact and simple frame.

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