scholarly journals Effects of external electric field and Al content on g factor of wurtzite AlGaN/GaN quantum wells

2018 ◽  
Vol 67 (5) ◽  
pp. 057101
Author(s):  
Li Ming ◽  
Yao Ning ◽  
Feng Zhi-Bo ◽  
Han Hong-Pei ◽  
Zhao Zheng-Yin
Keyword(s):  
Electric Field ◽  
Quantum Wells ◽  
External Electric Field ◽  
G Factor ◽  
Al Content

scholarly journals Spin dynamics of carriers in GaAs quantum wells in an external electric field

2004 ◽  
Vol 69 (3) ◽  
Author(s):  
I. Ya. Gerlovin ◽  
Yu. K. Dolgikh ◽  
S. A. Eliseev ◽  
V. V. Ovsyankin ◽  
Yu. P. Efimov ◽  
...  
Keyword(s):  
Electric Field ◽  
Quantum Wells ◽  
External Electric Field ◽  
Spin Dynamics

scholarly journals Asymmetric double quantum wells with smoothed interfaces

Open Physics ◽  
2012 ◽  
Vol 10 (2) ◽  
Author(s):  
Vladimir Gavryushin
Keyword(s):  
Electric Field ◽  
Quantum Wells ◽  
External Electric Field ◽  
Energy Levels ◽  
Double Quantum ◽  
Inverse Population ◽  
Double Quantum Well ◽  
The One ◽  
Interface Disorder ◽  
Asymmetric Double Quantum Wells

AbstractWe have derived and analyzed the wavefunctions and energy states for an asymmetric double quantum well (ADQW), broadened due to interdiffusion or other static interface disorder effects, within a known discreet variable representative approach for solving the one-dimensional Schrodinger equation. The main advantage of this approach is that it yields the energy eigenvalues, and the eigenvectors, in semiconductor nanostructures of different shapes as well as the strengths of the optical transitions between them. The behaviour of ADQW states for the different mutual widths of coupled wells, for the different degree of broadening, and under increasing external electric field is investigated. We have found that interface broadening effects change and shift energy levels, not monotonously, but the resonant conditions near an energy of sub-band coupling regions do not strongly distort. Also, it is shown that an external electric field may help to achieve resonant conditions for inter-sub-band inverse population by intrawell emission of LO-phonons in diffuse ADQW.

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.

scholarly journals Formation of a Fast Charge Transfer Channel in Quasi-2D Perovskite Solar Cells through External Electric Field Modulation

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7402
Author(s):  
Xixiang Zhu ◽  
Liping Peng ◽  
Jinpeng Li ◽  
Haomiao Yu ◽  
Yulin Xie
Keyword(s):  
Solar Cells ◽  
Charge Transfer ◽  
Electric Field ◽  
Quantum Wells ◽  
External Electric Field ◽  
Perovskite Solar Cells ◽  
Fast Charge ◽  
Transfer Channel ◽  
Local Polarization ◽  
Field Modulation

Quasi-2D perovskites solar cells exhibit excellent environmental stability, but relatively low photovoltaic properties, compared with 3D perovskites solar cells. However, charge transport and extraction in quasi-2D perovskite solar cells are still limited by the inevitable quantum well effect, resulting in low power conversion efficiency (PCE). To date, most efforts concentrate on crystal orientation and favorable alignment during materials and films processing. In this paper, we demonstrated that the quasi-2D perovskite [(BA)2(MA)3Pb4I13 (n = 4)] solar cells show an optimized device performance through forming a fast charge transfer channel among 2D quantum wells through external electric field modulation, with appropriate modulation bias and time after the device has been fabricated. Essentially, ions will move directionally due to local polarization in quasi-2D perovskite solar cells under the action of electric field modulation. More importantly, the mobile ions function as a dopant to de-passivate the defects when releasing at grain boundaries, while decreasing built-in potential by applying forward modulation bias with proper modulation time. The capacitance-voltage characteristics indicate that electric field modulation can decrease the charge accumulation and improve the charge collection in quasi-2D perovskite solar cells. Photoluminescence (PL) studies confirm that the non-radiative recombination is reduced by electric field modulation, leading to enhanced charge transfer. Our work indicates that external electric field modulation is an effective method to form a fast charge transfer channel among 2D quantum wells, leading to enhanced charge transfer and charge collection through local polarization toward developing high–performance quasi-2D perovskite devices.

Quantum Confinement Stark Effect of Different Gainnas Quantum Well Structures

2013 ◽  
Vol 773 ◽  
pp. 622-627
Author(s):  
Ying Ning Qiu ◽  
Wei Sheng Lu ◽  
Stephane Calvez
Keyword(s):  
Electric Field ◽  
Quantum Well ◽  
Quantum Wells ◽  
External Electric Field ◽  
Quantum Confinement ◽  
Stark Effect ◽  
Band Gap Energy ◽  
Electron Effective Mass ◽  
Coupled Quantum Wells ◽  
Quantum Well Structures

The quantum confinement Stark effect of three types of GaInNAs quantum wells, namely single square quantum well, stepped quantum wells and coupled quantum wells, is investigated using the band anti-crossing model. The comparison between experimental observation and modeling result validate the modeling process. The effects of the external electric field and localized N states on the quantized energy shifts of these three structures are compared and analyzed. The external electric field applied to the QW not only changes the potential profile but also modulates the localized N states, which causes band gap energy shifts and increase of electron effective mass.

The electronic states and the optical absorption for an asymmetrical quantum well applied with an external electric field

2019 ◽  
Vol 33 (26) ◽  
pp. 1950301 ◽  
Author(s):  
Yu Liu ◽  
Youbin Yu
Keyword(s):  
Optical Absorption ◽  
Iterative Method ◽  
Electric Field ◽  
Quantum Well ◽  
Quantum Wells ◽  
External Electric Field ◽  
Electronic States ◽  
Matrix Approach ◽  
Absorption Coefficients ◽  
Asymmetric Quantum

Electric field influences on the electronic states and the optical absorption in an asymmetrical quantum well with semiparabolic potential are investigated. The formula for the absorption coefficients in this asymmetrical quantum well with electric field are deduced by applying iterative method and density-matrix approach. The results are discussed with GaAs/AlGaAs materials and show that the external electric field has a significant effect on the electronic states and absorption coefficients of asymmetric quantum wells.

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