GaAsN alloys belong to a class of semiconductors with fascinating physical properties. Indeed, a small amount of nitrogen incorporation in GaAs leads to a counterintuitive and large band-gap reduction, and to an unexpected sudden increase in the effective mass of electrons. Even more surprisingly, both electronic and structural changes can be reversed fully and in a tunable manner by hydrogen incorporation. In this paper, we combine x-ray absorption spectroscopy at the nitrogen edge with ab initio simulations to investigate the atomic geometry of N-H complexes in hydrogenated GaAsN. In this way, we provide experimental evidence that dihydrogen-nitrogen complexes with C2v symmetry are the most abundant species in hydrogenated GaAsN. This finding contradicts previous predictions of “in-line” N-H2 * complexes as the predominant species, and accounts for recent infrared absorption experiments.
Titolo: | A new nitrogen-hydrogen complex in GaAsN revealed by X ray absorption spectroscopy |
Autore/i: | G. Ciatto; BOSCHERINI, FEDERICO; A. Amore Bonapasta; F. Filippone; A. Polimeni; M. Capizzi |
Autore/i Unibo: | |
Anno: | 2005 |
Rivista: | |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1103/PhysRevB.71.201301 |
Abstract: | GaAsN alloys belong to a class of semiconductors with fascinating physical properties. Indeed, a small amount of nitrogen incorporation in GaAs leads to a counterintuitive and large band-gap reduction, and to an unexpected sudden increase in the effective mass of electrons. Even more surprisingly, both electronic and structural changes can be reversed fully and in a tunable manner by hydrogen incorporation. In this paper, we combine x-ray absorption spectroscopy at the nitrogen edge with ab initio simulations to investigate the atomic geometry of N-H complexes in hydrogenated GaAsN. In this way, we provide experimental evidence that dihydrogen-nitrogen complexes with C2v symmetry are the most abundant species in hydrogenated GaAsN. This finding contradicts previous predictions of “in-line” N-H2 * complexes as the predominant species, and accounts for recent infrared absorption experiments. |
Data prodotto definitivo in UGOV: | 2005-09-23 23:10:26 |
Appare nelle tipologie: | 1.01 Articolo in rivista |