Optical Characterization of AlGaN/GaN MQW's

2000 ◽  
Vol 639 ◽  
Author(s):  
Ricardo A. Rocha ◽  
Teresa Monteiro ◽  
Estela Pereira ◽  
Eduardo Alves
Keyword(s):  
Electric Field ◽  
Quantum Wells ◽  
Electric Fields ◽  
Stark Effect ◽  
Theoretical Models ◽  
Optical Characterization ◽  
Photoluminescence Spectra

ABSTRACTAlGaN/GaN multi-quantum wells (MQW's) were optically studied in this work. Photoluminescence spectra revealed a quantum Stark effect in the samples. Calculated builtin electric fields were found to be significantly less than the values expected from theoretical models. An approach concerning the existence of free charges responsible for screening of the electric field is made, where we find carrier densities very similar to values described in other works.

Intersubband Transitions in Asymmetric Quantum Wells with External Electric Field

2014 ◽  
Vol 525 ◽  
pp. 170-176
Author(s):  
Zhao Xu Liu ◽  
Jun Zhu ◽  
Si Hua Ha
Keyword(s):  
Electric Field ◽  
Quantum Wells ◽  
External Electric Field ◽  
Electric Fields ◽  
Stark Effect ◽  
Energy Levels ◽  
Intersubband Transitions ◽  
External Electric Fields ◽  
Asymmetric Quantum ◽  
Negative Field

The quantum-confined Stark effect on the optical absorption of intersubband transitions in an asymmetric AlxGa1-xN/In0.3Ga0.7N/GaN quantum wells is investigated by means of the density matrix formulism. The built-in electric field generated by the piezoelectric and spontaneous polarizations competing against to the external electric fields is considered. As the result, the influences of the built-in and external electric fields on the energy potentials and the eigen stares are discussed in detail. When the positive external electric field is applied, the peak values of the absorption coefficients from 3-2, 2-1 and 3-1 transitions are reduced and moved to the lower photon energy levels. With the negative field, the exactly opposite results can be obtained. Moreover, it is indicated that the results of the wavelengths from the 3-2, 2-1 and 3-1 transitions are reduced by the positive external electric field and increased by the negative field.

Electric Field Effects on the Optical Properties of InxGa1-xAs/GaAs Strained Quantum Wells and Superlattices

1989 ◽  
Vol 160 ◽  
Author(s):  
K. Gibb ◽  
C. Lacelle ◽  
A.P. Roth ◽  
B. Soucail ◽  
N. Dupuis ◽  
...  
Keyword(s):  
Electric Field ◽  
Quantum Wells ◽  
Electric Fields ◽  
Stark Effect ◽  
Energy Levels ◽  
Precise Determination ◽  
Discrete Energy ◽  
Photocurrent Spectroscopy ◽  
Zone Centre ◽  
Photocurrent Spectra

AbstractWe have used photoluminescence excitation and photocurrent spectroscopy to investigate the electronic properties of InxGa1-xAs/GaAs strained layer quantum wells and superlattices. In quantum wells, sharp excitonic transitions between discrete energy levels are observed both in excitation and near flatband photocurrent spectra whereas superlattices show heavy-hole to conduction miniband transitions at the Brillouin mini-zone centre and edge, directly giving the electron miniband width. Applying a longitudinal electric field to the quantum wells produces a red shift of the excitons due to the quantum confined Stark effect, while in superlattices, photocurrent spectra at finite applied electric fields show for the first time in this system, the effects of Wannier-Stark quantization. The analysis of the spectra provides a precise determination of the band offset.

Optical characterization of type-II ZnO/ZnS multiple quantum wells grown by atomic layer deposition

2020 ◽  
Vol 694 ◽  
pp. 137740 ◽  
Author(s):  
Mostafa Afifi Hassan ◽  
Aadil Waseem ◽  
Muhammad Ali Johar ◽  
Sou Young Yu ◽  
June Key Lee ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Quantum Wells ◽  
Atomic Layer ◽  
Optical Characterization ◽  
Multiple Quantum Wells ◽  
Multiple Quantum ◽  
Type Ii ◽  
Layer Deposition

scholarly journals Piezoelectric Level Splitting in GaInN/GaN Quantum Wells

1999 ◽  
Vol 4 (S1) ◽  
pp. 357-362
Author(s):  
C. Wetzel ◽  
T. Takeuchi ◽  
H. Amano ◽  
I. Akasaki
Keyword(s):  
Quantum Wells ◽  
Electric Fields ◽  
High Performance ◽  
Stark Effect ◽  
Electronic Band Structure ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Large Set ◽  
Electronic Band ◽  
Level Splitting

Identification of the electronic band structure in AlInGaN heterostructures is the key issue in high performance light emitter and switching devices. In device-typical GaInN/GaN multiple quantum well samples in a large set of variable composition a clear correspondence of transitions in photo- and electroreflection, as well as photoluminescence is found. The effective band offset across the GaN/GaInN/GaN piezoelectric heterointerface is identified and electric fields from 0.23 - 0.90 MV/cm are directly derived. In the bias voltage dependence a level splitting within the well is observed accompanied by the quantum confined Stark effect. We furthermore find direct correspondence of luminescence bands with reflectance features. This indicates the dominating role of piezoelectric fields in the bandstructure of such typical strained layers.

Optical characterization of ZnSe epilayers and ZnCdSe∕ZnSe quantum wells grown on Ge∕Ge0.95Si0.05∕Ge0.9Si0.1∕Si virtual substrates

2006 ◽  
Vol 99 (6) ◽  
pp. 063506 ◽  
Author(s):  
J. T. Ku ◽  
M. C. Kuo ◽  
J. L. Shen ◽  
K. C. Chiu ◽  
T. H. Yang ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Optical Characterization

Optical Characterization of a 20 Layer AlGaAs/GaAs Multiple Quantum Wells

2018 ◽  
Vol 73 (5) ◽  
pp. 632-637
Author(s):  
Luqman Ali ◽  
Janghyun Cho ◽  
Clare Chisu Byeon ◽  
Jin Dong Song ◽  
Hyun-Jun Jo ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Optical Characterization ◽  
Multiple Quantum Wells ◽  
Multiple Quantum

Electric Field-Assisted Positioning of Neurons on Pt Microelectrode Arrays

2003 ◽  
Vol 773 ◽  
Author(s):  
Shalini Prasad ◽  
Mo Yang ◽  
Xuan Zhang ◽  
Yingchun Ni ◽  
Vladimir Parpura ◽  
...  
Keyword(s):  
Electric Field ◽  
Electrical Activity ◽  
Electric Fields ◽  
Microelectrode Array ◽  
Electrode Array ◽  
Sprague Dawley ◽  
A Cell ◽  
Neuron Patterning

AbstractCharacterization of electrical activity of individual neurons is the fundamental step in understanding the functioning of the nervous system. Single cell electrical activity at various stages of cell development is essential to accurately determine in in-vivo conditions the position of a cell based on the procured electrical activity. Understanding memory formation and development translates to changes in the electrical activity of individual neurons. Hence, there is an enormous need to develop novel ways for isolating and positioning individual neurons over single recording sites. To this end, we used a 3x3 multiple microelectrode array system to spatially arrange neurons by applying a gradient AC field. We characterized the electric field distribution inside our test platform by using two dimensiona l finite element modeling (FEM) and determined the location of neurons over the electrode array. Dielectrophoretic AC fields were utilized to separate the neurons from the glial cells and to position the neurons over the electrodes. The neurons were obtained from 0-2-day-old rat (Sprague-Dawley) pups. The technique of using electric fields to achieve single neuron patterning has implications in neural engineering, elucidating a new and simpler method to develop and study neuronal activity as compared to conventional microelectrode array techniques.

scholarly journals Piezoelectric Level Splitting in GaInN/GaN Quantum Wells

1998 ◽  
Vol 537 ◽  
Author(s):  
C. Wetzel ◽  
T. Takeuchi ◽  
H. Amano ◽  
I. Akasaki
Keyword(s):  
Quantum Wells ◽  
Electric Fields ◽  
High Performance ◽  
Stark Effect ◽  
Electronic Band Structure ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Large Set ◽  
Electronic Band ◽  
Level Splitting

AbstractIdentification of the electronic band structure in AlInGaN heterostructures is the key issue in high performance light emitter and switching devices. In device-typical GaInN/GaN multiple quantum well samples in a large set of variable composition a clear correspondence of transitions in photo- and electroreflection, as well as photoluminescence is found. The effective band offset across the GaN/GaInN/GaN piezoelectric heterointerface is identified and electric fields from 0.23 - 0.90 MV/cm are directly derived. In the bias voltage dependence a level splitting within the well is observed accompanied by the quantum confined Stark effect. We furthermore find direct correspondence of luminescence bands with reflectance features. This indicates the dominating role of piezoelectric fields in the bandstructure of such typical strained layers.

Sign in / Sign up

Export Citation Format

Share Document