DX-center formation in wurtzite and zinc-blende AlxGa12xN
نویسنده
چکیده
The transition from shallow to deep centers as a function of pressure or alloying is investigated for oxygen and silicon donors in GaN and AlN, based on first-principles total-energy calculations. The stability of the localized deep state (DX center! is found to depend on interactions between the impurity and third-nearestneighbor atoms, which occur in different positions in the zinc-blende and the wurtzite phase. DX-center formation is suppressed in the zinc-blende phase, as well as for silicon donors. The results strengthen the identification of oxygen as the unintentional dopant in n-type GaN, and shed new light on the driving force for DX formation. @S0163-1829~98!50404-3#
منابع مشابه
Phase controlled synthesis of ZnS nanobelts: zinc blende vs wurtzite
Bulk crystals of ZnS usually take the zinc blende structure. However, the vapor deposited one-dimensional ZnS nanostructures normally take the metastable wurtzite structure. This Letter investigates the conditions under which the formed phase can be controlled between zinc blende and wurtzite in nanomaterials synthesis. The formation of pure zinc blende structured ZnS nanobelts is related not o...
متن کاملWhy does wurtzite form in nanowires of III-V zinc blende semiconductors?
We develop a nucleation-based model to explain the formation of the wurtzite phase during the catalyzed growth of freestanding nanowires of zinc blende semiconductors. We show that in vapor-liquid-solid nanowire growth, nucleation generally occurs preferentially at the triple phase line. This entails major differences between zinc blende and wurtzite nuclei. Depending on the pertinent interface...
متن کاملMechanical, Thermodynamic and Electronic Properties of Wurtzite and Zinc-Blende GaN Crystals
For the limitation of experimental methods in crystal characterization, in this study, the mechanical, thermodynamic and electronic properties of wurtzite and zinc-blende GaN crystals were investigated by first-principles calculations based on density functional theory. Firstly, bulk moduli, shear moduli, elastic moduli and Poisson's ratios of the two GaN polycrystals were calculated using Voig...
متن کاملElectronic and structural characteristics of zinc-blende wurtzite biphasic homostructure GaN nanowires.
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 microscopy was used to identify distinct wurtzite and zinc-blende crystalline phases within single nanowires through the use of selected area electron diffraction...
متن کاملSize- and shape-dependent phase transformations in wurtzite ZnS nanostructures.
This paper describes the equilibrium morphologies of zinc sulfide nanoparticles in the wurtzite phase as a function of size, determined using ab initio Density Functional Theory (DFT) simulations and a shape-dependent thermodynamic model predicting the Gibbs free energy of a nanoparticle. We investigate the relative stabilities of a variety of nanoparticle shapes based on the wurtzite structure...
متن کامل