Phonon Spectrum of Led InGaN/GaN Heterostructure with Quantum Wells

2021 ◽  
Author(s):  
V. N. Davydov ◽  
A. N. Lapin ◽  
O. F. Zadorozhny
Keyword(s):  
Quantum Wells ◽  
Phonon Spectrum ◽  
Gan Heterostructure

Phonon spectrum of LED InGaN/GaN heterostructure with quantum wells

2021 ◽  
pp. 144-147
Author(s):  
V.N. Davydov ◽  
◽  
A.N. Lapin ◽  
O.F. Zadorozhny ◽  
◽  
...  
Keyword(s):  
Experimental Data ◽  
Energy Spectrum ◽  
Quantum Wells ◽  
Barrier Layer ◽  
Phonon Spectrum ◽  
Radiation Level ◽  
Dimensional Quantization ◽  
Upper Level ◽  
Gan Heterostructure ◽  
Comparison Of The Results

Measurements of the phonon spectrum of the LED heterostructure based on the In0.12Ga0.88N/GaN barrier showed the presence in it of four peaks of phonon radiation with energies of 0.193, 0.207, 0.353, and 0.356 eV. From a comparison of the results of the calculation of the energy spectrum of the electron and hole quantum wells with the obtained experimental data, it was assumed that these peaks can be interpreted as the energies of phonons generated during the capture of electrons from the barrier layer to the second level of dimensional quantization, as well as during the relaxation of electrons from the second level to the radiation level and trapping holes to the upper level of the quantum well.

Diagnostics of semiconductor structures by electrochemical capacitance-voltage profiling technique

2021 ◽  
Vol 87 (1) ◽  
pp. 35-44
Author(s):  
G. E. Yakovlev ◽  
D. S. Frolov ◽  
V. I. Zubkov
Keyword(s):  
Quantum Wells ◽  
Concentration Distribution ◽  
Semiconductor Devices ◽  
Multiple Quantum ◽  
Carrier Distribution ◽  
Electrochemical Capacitance ◽  
Informative Feedback ◽  
Semiconductor Structures ◽  
Capacitance Voltage ◽  
Gan Heterostructure

The properties of interfaces in the heterostructures which frequently govern their operation are of particular importance for the devices containing heterostructures as active elements. Any further improving of the characteristics of semiconductor devices is impossible without a detail analysis of the processes occurring at the interfaces of heterojunctions. At the same time, the results largely depend on the purity of the starting materials and the technology of layer manufacturing. Moreover, the requirements to the composition and distribution of the impurity steadily get stringent. Therefore, the requirements regarding the methods of the impurity control and carrier distribution also become tougher both in the stage of laboratory development of the structure and in various stages of manufacturing of semiconductor devices. Electrochemical capacitance-voltage profiling is distinguished among the methods of electrical diagnostics of semiconductors by the absence of special preparation of the structures and deposition of the contacts to perform measurements, thus providing for gaining information not only about the impurity distribution but also about the distribution of free carriers. The goal of this work is to perform precise measurements of the profiles of free carrier distribution in semiconductor structures of different types, and demonstrate the measuring capabilities of a modern technique for concentration distribution diagnostics, i.e., electrochemical capacitance-voltage profiling. The method allows verification of the layer thickness in semiconductor heterostructures and provide a useful and informative feedback to technologists. To increase the resolution of the method and broad up the range of available test frequencies, a standard electrochemical profiler has been modified. Mapping data for GaAs substrate structure, the profiles of the concentration distribution of the majority charge carriers in SiC structures, GaAs structure with a p – n junction, pHEMT heterostructure, GaN heterostructure with multiple quantum wells, and in a silicon-based solar cell heterostructure are presented. The obtained results can be used to analyze the physical properties and phenomena in semiconductor devices with quantum-sized layers, as well as to improve and refine the parameters of existing electronic devices.

Electron-Phonon Scattering in GaN/AlN and GaAs/AlAs Quantum Wells

1997 ◽  
Vol 482 ◽  
Author(s):  
T. F. Forbang ◽  
C. R. McIntyre
Keyword(s):  
Quantum Wells ◽  
Optical Phonon ◽  
Phonon Spectrum ◽  
Phonon Scattering ◽  
Relaxation Times ◽  
Longitudinal Optical ◽  
Longitudinal Optical Phonon ◽  
Phonon Modes ◽  
Optical Phonon Scattering ◽  
Electron Phonon Scattering

AbstractWe have studied the effects on the phonon spectrum and on the electron-longitudinal optical phonon scattering in GaN/AlN and GaAs/AlAs quantum wells. Phonon modes and potentials have been calculated for both systems. Results for emission due to electroninterface phonons interactions are presented. We will discuss the implications for relaxation times and electron mobility due to modified LO-phonon scattering in both systems.

Confinement effects on the phonon spectrum of thin InAs/InP strained single quantum wells

1994 ◽  
Vol 9 (3) ◽  
pp. 256-262 ◽  
Author(s):  
L Pavesi ◽  
G Mariotto ◽  
J F Carlin ◽  
A Rudra ◽  
L Colombo
Keyword(s):  
Quantum Wells ◽  
Phonon Spectrum ◽  
Single Quantum ◽  
Confinement Effects

Growth of High Quality (In,Ga,Al)N/GaN Heterostructure Materials and Devices by Atmospheric Pressure MOCVD

1996 ◽  
Vol 423 ◽  
Author(s):  
S. P. Denbaars ◽  
S. Keller ◽  
B. P. Keller ◽  
Y. F. Wu ◽  
D. Kapolnek ◽  
...  
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Atmospheric Pressure ◽  
Impurity Level ◽  
Single Quantum ◽  
High Quality ◽  
Single Quantum Well ◽  
Background Impurity ◽  
Direct Band ◽  
Gan Heterostructure

AbstractUsing atmospheric pressure MOCVD we have obtained high quality InGaN/GaN and AlGaN/GaN heterostructure materials and devices. For nominally undoped 4 μm thick GaN films, we obtained 300 K mobilities of 780 cm2/Vs and an unintentional background impurity level of n300K = 6*1016 cm−3. For InGaN/GaN heterostructures we have obtained direct band-edge transitions with FWHM as narrow as 7.9 nm (59 meV) for 50Å thick In0.16Ga0.84N quantum wells at 300K, which is the among the best reported values. The quantum wells display energy shifts towards shorter wavelength with decreasing well thickness, and the shift agrees with predicted quantum effects. These materials have been incorporated into InGaN single quantum well LEDs that emit at 450 nm. In addition AlGaN/GaN heterostructure materials have been incorporated into HFETs and MODFETs. Gate-drain breakdown voltage well exceeding 100 V, and extrinsic transconductance gm of up to 140 mS/mm were realized in the MODFET.

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.

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