Columnar [001]-oriented nitrogen order in Ga(NAs) and (GaIn)(NAs) alloys

Abstract

By calculations in the framework of the valence force field method, we show that nitrogen atoms in diluted GaAs 1−x N x tend to align along the [001] direction. In quaternary alloys Ga 1−y In y As 1−x N x this tendency is observed only in "as-grown" samples, while in the annealed samples nitrogen atoms build more energetically favorable bonds with indium. Experimentally observed inhomogeneous strain profiles in these material systems, as well as their dissolution upon annealing, agree qualitatively with results of the calculations.

Influence of annealing on the optical and structural properties of dilute N-containing III/V semiconductor heterostructures

“…They extend through the complete well and have a lateral distance in the range of 10 nm. We have attributed these strain fluctuations, which we detected in the materials as soon as N was contained in the structure, to chain-like ordering of N-atoms in growth direction, which is the stable configuration upon growth [19,20]. These N-chains, containing increased amounts of N as compared to the surround (GaIn)(NAs) matrix, might also act as nonradiative centers in the material, trapping carriers very efficiently and hence be responsible for low PL intensities after growth.…”

“…One knows that N, which has four Ga-atoms as nearest neighbours during growth, moves to a more In-rich environment upon annealing. This process is driven by the decrease in strain-energy of the crystal [19,20], as the InN bond length is closer to that of GaAs than the GaN one. This process is initiated by the generation of As vacancies, as they generate the empty group-V lattice sites, Fig.…”

Optimization of annealing conditions of (GaIn)(NAs) for solar cell applications

“…Several structural characteristics, such as chain like N-ordering in growth direction, as will be outlined in the following, are however intrinsic to the dilute-N-containing material systems [11][12][13].…”

MOVPE growth of dilute nitride III/V semiconductors using all liquid metalorganic precursors

“…This is explained by the large difference between the covalent radii of N on the one side and As on the other side. Due to the metastability also the comprehension of phase-separation and of the structural development in dependence on growth conditions, annealing procedures and composition is of key importance and is detailed in separate papers [31][32][33][34][35][36].…”