Browsing by Author "Chen, Chun-Nan"

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Application of Block Diagonal Technique to a Hamiltonian Matrix in Performing Spin-splitting Calculations for GaN Wurtzite Materials
(2012-02-01)
Chen, Chun-Nan
;
Chang, Sheng-Hsiung
;
Su, Wei-Long
;
Wang, Wan-Tsang
;
Kao, Hsiu-Fen
The bulk inversion asymmetry (Dresselhaus) terms (i.e., B-2, B-1, and B'(1) terms) of wurtzite materials are determined. The 2 x 2 conduction band, 2 x 2 heavy-hole band, 2 x 2 light-hole band, and 2 x 2 crystal-field split-off hole band matrices of wurtzite semiconductors are developed and decoupled by using a block diagonal technique. Importantly, those 2 x 2 block diagonal matrices incorporate not only the interband coupling effect but also the bulk inversion asymmetry effect. Analytical expressions for the conduction and the valence band spin-splitting parameters and energies of GaN wurtzite materials are formulated by solving the block diagonal matrices. The presence of these terms is shown to include the spin-splitting phenomenon.
Device Simulation-Based Multiobjective Evolutionary Algorithm for Process Optimization of Semiconductor Solar Cells
(2013-07-03)
Li, Yiming
;
Chen, Yu-Yu
;
Chen, Chieh-Yang
;
Shen, Cheng-Han
;
Cheng, Hui-Wen
This article implements for the first time a numerical semiconductor device simulation-based multiobjective evolutionary algorithm (MOEA) for the characteristic optimization of amorphous silicon thin-film solar cells, based upon a unified optimization framework (UOF). To calculate the device's characteristic, a set of coupled solar cell transport equations consisting of the Poisson equation, the electron-hole current continuity equations, and the photo-generation model is solved numerically. Electrical characteristics, the short-circuited current, the open-circuited voltage, and the conversion efficiency are calculated to analyze the properties of the explored solar cells. The aforementioned device simulation results are used to evaluate the fitness score and access the evolutionary quality of designing parameters via the implemented non-dominating sorting genetic algorithm (NSGA-II) in the UOF. Notably, designing parameters including the material and structural parameters, and the doping concentrations are simultaneously optimized for the explored solar cells. The simulation-based MOEA methodology is useful in optimal structure design and manufacturing of semiconductor solar cells.
General Expressions for Ellipsoidal-Valley Quantum Transport in Arbitrary Growth Direction: Non-Equilibrium Green's Function
(2011-06-01)
Chen, Chun-Nan
;
Su, Wei-Long
;
Lee, Meng-En
;
Jen, Jen-Yi
;
Li, Yiming
A theoretical method for the calculation of quantum transport in an ellipsoidal valley is presented. This method is developed using a non-equilibrium Green's function framework. Importantly, it is instructive that k(z) is separated into two parts so that the wrong figure shape of the transmission coefficients does not exist. The L-electron effect on AlAs-GaAs-AlAs double barrier structures oriented in the [001], [111], and [110] growth directions is explored using the proposed method. (C) 2011 The Japan Society of Applied Physics
k center dot p Zincblende Hamiltonian and Optical Matrix with Bulk Inversion Asymmetry
(2011-08-01)
Chen, Chun-Nan
;
Su, Wei-Long
;
Lee, Meng-En
;
Jen, Jen-Yi
;
Li, Yiming
A conventional 8 x 8 k.p zincblende Hamiltonian is corrected to include the bulk (or intracell) inversion asymmetry. Meanwhile, a conventional 8 x 8 k.p zincblende optical matrix is also corrected to include this intracell asymmetry. (C) 2011 The Japan Society of Applied Physics
k.p WURTZITE HAMILTONIAN AND OPTICAL MATRIX WITH BULK INVERSION ASYMMETRY
(2012-01-10)
Chen, Chun-Nan
;
Su, Wei-Long
;
Wang, Wan-Tsang
;
Jen, Jen-Yi
;
Li, Yiming
A k.p wurtzite Hamiltonian including the bulk (or intracell) inversion asymmetry is developed. Meanwhile, a k.p wurtzite optical matrix including this intracell asymmetry is also established.
Multiband treatment of quantum transport in anisotropic semiconductors: Non-equilibrium Green's function
(2013-07-01)
Chen, Chun-Nan
;
Chang, Sheng-Hsiung
;
Su, Wei-Long
;
Jen, Jen-Yi
;
Li, Yiming
Using the non-equilibrium Green's function and anti-bonding orbital model, a multiband treatment of quantum transport in an anisotropic semiconductor (Si-based) system is developed. In this study, we adopt Chiang's boundary treatment of the open boundary system into the non-equilibrium Green's function framework, and then an easy and powerful multiband treatment method is developed to solve the transmission coefficient of Si-based semiconductor quantum structures. (C) 2012 Elsevier Ltd. All rights reserved.
Preface
(2013-07-01)
Li, Yiming
;
Chen, Chun-Nan
;
Kamakura, Yoshinari
;
McKenzie, Todd
;
Shin, Mincheol
Velocity-direction dependent transmission coefficient of electron through potential barrier grown on anisotropic semiconductor
(2012-09-01)
Chen, Chun-Nan
;
Chang, Sheng-Hsiung
;
Su, Wei-Long
;
Jen, Jen-Yi
;
Li, Yiming
In contrast to the usual wavevector dependent transition coefficients, the velocity-direction dependent transition coefficients of an incident electron are calculated. Through a potential barrier grown on anisotropic semiconductors, the transition coefficients of an incident electron are calculated in all valleys and incident-directions. In the anisotropic semiconductor, the mathematical expressions of the electron wavevector are also derived in the framework of the incident-angle and incident-energy parameters.