The Electronic Structure and Transmission Characteristics of Disordered AlGaAs Nanowires

Perfect nanowires may be studied from both the bandstructure and transmission perspectives, and relating features in one set of curves to those in another often yields much insight into their behavior. For random-alloy nanowires, however, only transmission characteristics and virtual-crystal approximation (VCA) bands have been available. This is a serious shortcoming since the VCA cannot properly capture disorder at the primitive cell level: those bulk properties which it can satisfactorily reproduce arise from spatially extended states and measurements which average out primitive cell-level fluctuations. Here we address this deficiency by projecting approximate bands out of supercell states for Al0.15Ga0.85As random alloy nanowires. The resulting bands correspond to the transmission characteristics very closely, unlike the VCA bands, which cannot explain important transmission features. Using both bandstructure and transmission results, we are better able to explain the operation of these nanowires

[1]  A. Carlo,et al.  OFF-RESONANCE GAMMA -X MIXING IN SEMICONDUCTOR QUANTUM WIRES , 1998 .

[2]  Yia-Chung Chang,et al.  Systematic study of Ga1−xInxAs self-assembled quantum wires with varying interfacial strain relaxation , 2000, cond-mat/0005392.

[3]  Strain effect in a GaAs-In0.25Ga0.75As-Al0.5Ga0.5As asymmetric quantum wire , 2000 .

[4]  Boundary conditions for the electronic structure of finite-extent embedded semiconductor nanostructures , 2003, cond-mat/0311461.

[5]  Mincheol Shin,et al.  Effects of atomistic defects on coherent electron transmission in Si nanowires: Full band calculations , 2001 .

[6]  B. Bouhafs,et al.  Electronic structure of AlxGa1 − xAs and GaPxAs1 − x alloys modified virtual crystal approximation calculation using sp3s* band structures , 1996 .

[7]  Gerhard Klimeck,et al.  Practical application of zone-folding concepts in tight-binding calculations , 2005 .

[8]  Paolo Lugli,et al.  CONDUCTION-BAND MIXING IN T- AND V-SHAPED QUANTUM WIRES , 1997 .

[9]  G. P. Triberis,et al.  Mobility in V-shaped quantum wires due to interface roughness and alloy scattering , 2004 .

[10]  Morten Willatzen,et al.  Electron states in modulated nanowires , 2003 .

[11]  Lee,et al.  Band structure of ternary-compound semiconductors using a modified tight-binding method. , 1990, Physical review. B, Condensed matter.

[12]  Finite element analysis of strain effects on electronic and transport properties in quantum dots and wires , 1998, cond-mat/9806029.

[13]  Gerhard Klimeck,et al.  Approximate bandstructures of semiconductor alloys from tight-binding supercell calculations , 2007, Journal of Physics: Condensed Matter.

[14]  Gerhard Klimeck,et al.  Quantitative simulation of a resonant tunneling diode , 1997, Journal of Applied Physics.

[15]  Gerhard Klimeck,et al.  Quantum device simulation with a generalized tunneling formula , 1995 .

[16]  Fabio Beltram,et al.  Empirical spds^* tight-binding calculation for cubic semiconductors : general method and material parameters , 1998 .

[17]  S. Jaziri,et al.  Excitonic states of weakly confining quantum wires , 1998 .

[18]  Zunger,et al.  Quantum-confinement-induced Gamma -->X transition in GaAs/AlGaAs quantum films, wires, and dots. , 1995, Physical review. B, Condensed matter.

[19]  Hongqi Xu,et al.  Giant polarization anisotropy in optical transitions of free-standing InP nanowires , 2004 .

[20]  L. Voon,et al.  Prediction of barrier localization in modulated nanowires , 2004 .

[21]  W. Fichtner,et al.  Atomistic simulation of nanowires in the sp3d5s* tight-binding formalism: From boundary conditions to strain calculations , 2006 .

[22]  Gerhard Klimeck,et al.  Development of a Nanoelectronic 3-D (NEMO 3-D ) Simulator for Multimillion Atom Simulations and Its Application to Alloyed Quantum Dots , 2002 .