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Huge built-in electric fields have been predicted to exist in wurtzite III-V nitrides thin films and multilayers. Such fields originate from heterointerface discontinuities of the macroscopic bulk polarization of the nitrides. Here we…

Materials Science · Physics 2009-10-31 V. Fiorentini , F. Bernardini , F. Della Sala , A. Di Carlo , P. Lugli

Huge built-in electric fields have been predicted to exist in wurtzite III-V nitrides thin films and multilayers. Such fields originate from heterointerface discontinuities of the macroscopic bulk polarization of the nitrides. Here we…

Materials Science · Physics 2007-05-23 V. Fiorentini , F. Bernardini , F. Della Sala , A. DiCarlo , P. Lugli

Semiconductor lasers are strongly altered by adding spin-polarized carriers. Such spin lasers could overcome many limitations of their conventional (spin-unpolarized) counterparts. While the vast majority of experiments in spin lasers…

Mesoscale and Nanoscale Physics · Physics 2017-04-05 Paulo E. Faria Junior , Gaofeng Xu , Yang-Fang Chen , Guilherme M. Sipahi , Igor Žutić

We present a study of the polarization properties of emission lines from single InGaN/GaN quantum dots (QDs). The QDs, formed by spinodal decomposition within ultra-thin InGaN quantum wells, are investigated using single-QD…

Materials Science · Physics 2008-06-13 M. Winkelnkemper , R. Seguin , S. Rodt , A. Schliwa , L. Reissmann , A. Strittmatter , A. Hoffmann , D. Bimberg

The spontaneous polarization of wurtzite III-V nitrides XN (X=Al, Ga, In) and II-VI oxides YO (Y=Be, Zn) is investigated via first-principles computational methods. The modern treatment defines this quantity as the polarization difference…

Huge built-in electric fields are predicted to exist in wurtzite III-V nitrides thin films and multilayers. Such fields originate from heterointerface discontinuities of the macroscopic bulk polarization of the nitrides. We discuss the…

Materials Science · Physics 2007-05-23 Fabio Bernardini , Vincenzo Fiorentini

We present a study of undoped AlGaN/GaN separate confinement heterostructures designed to operate as electron beam pumped ultraviolet lasers. We discuss the effect of spontaneous and piezoelectric polarization on carrier diffusion,…

The wurtzite structure is one of the most frequently found crystal structures in modern semiconductors and its inherent spontaneous polarization is a defining materials property. Despite this significance, confusion has been rampant in the…

Materials Science · Physics 2025-05-07 Simon Fichtner , Mohamed Yassine , Chris van de Walle , Oliver Ambacher

The discovery of ferroelectricity in wurtzite nitrides has paved the way for measuring and understanding spontaneous polarization in III-V semiconductors. However, the calculation of polarization effects at heterointerfaces - crucial for…

Materials Science · Physics 2025-05-27 Jesus Cañas , Mohamed Yassine , Oliver Ambacher

Bandstructure properties in wurtzite quantum wells can change appreciably with changing carrier density because of screening of quantum-confined Stark effect. An approach for incorporating these changes in an InGaN light-emitting-diode…

Optics · Physics 2015-05-28 Weng W. Chow

Low threshold lasers realized within compact, high quality optical cavities enable a variety of nanophotonics applications. Gallium nitride (GaN) materials containing indium gallium nitride (InGaN) quantum dots and quantum wells offer an…

Photoluminescence measurements on high-quality InGaN quantum wells reveal that carriers diffuse laterally to long distances at room temperature, up to tens of microns. This behavior, which shows a pronounced dependence on the excitation…

Materials Science · Physics 2021-05-19 Aurelien David

Aluminium Gallium Nitride ((Al,Ga)N) presents an ideal platform for designing ultra-violet (UV) light emitters across the entire UV spectral range. However, in the deep-UV spectral range (<280 nm) these emitters exhibit very low quantum…

Materials Science · Physics 2025-01-29 Robert Finn , Michael O'Donovan , Thomas Koprucki , Stefan Schulz

Ab initio electronic structure studies of prototypical polar interfaces of wurtzite III-V nitrides show that large uniform electric fields exist in epitaxial nitride overlayers, due to the discontinuity across the interface of the…

Materials Science · Physics 2009-10-30 Fabio Bernardini , Vincenzo Fiorentini

Exploring the limits of spontaneous emission coupling is not only one of the central goals in the development of nanolasers, it is also highly relevant regarding future large-scale photonic integration requiring energy-efficient coherent…

Accurate values for polarization discontinuities between pyroelectric materials are critical for understanding and designing the electronic properties of heterostructures. For wurtzite materials, the zincblende structure has been used in…

Materials Science · Physics 2018-04-17 Cyrus E. Dreyer , Anderson Janotti , Chris G. Van de Walle , David Vanderbilt

The spontaneous polarization, dynamical Born charges, and piezoelectric constants of the III-V nitrides AlN, GaN, and InN are studied ab initio using the Berry phase approach to polarization in solids. The piezoelectric constants are found…

Materials Science · Physics 2009-10-30 Fabio Bernardini , Vincenzo Fiorentini , David Vanderbilt

We report a new biphasic crystalline wurtzite/zinc-blende homostructure in gallium nitride nanowires. Cathodoluminescence was used to quantitatively measure the wurtzite and zinc-blende band gaps. High resolution transmission electron…

We present a theory of local electric polarization in crystalline solids and apply it to study the case of wurtzite group-III nitrides. We show that a local value of the electric polarization, evaluated at the atomic sites, can be cast in…

Materials Science · Physics 2013-12-06 Miguel A. Caro , Stefan Schulz , Eoin P. O'Reilly

The degree of ionisation of a two-dimensional electron-hole plasma is calculated in the low-density (Boltzmann) limit. The electron-hole interaction is considered for all states: optically active and inactive, bound and unbound. The theory…

Statistical Mechanics · Physics 2015-06-24 M. E. Portnoi , I. Galbraith
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