Hydrogen diffusion inGaAs1−xNx

Abstract

Hydrogen ͑or deuterium͒ incorporation in dilute nitride semiconductors modifies dramatically the electronic and structural properties of the crystal through the creation of nitrogen-hydrogen complexes. In this work, we investigate how the formation and dissociation of such complexes rule the diffusion of deuterium in GaAs 1−x N x . The concentration depth profile of deuterium is determined by secondary ion mass spectrometry under a wide range of experimental conditions that comprise different N concentrations ͑x = 0.09%, 0.40%, 0.70%, and 1.5%͒ and D irradiation temperatures ͑T D = 200, 250, 300 and 350°C͒. The experimental data are successfully reproduced by a diffusion model in the presence of strong D trapping. In particular, the deuterium diffusion and capture rate coefficients are determined, and a minimum decay length of the deuterium forefront is found at low T D ͑Ͻ250°C͒ and high x ͑Ͼ0.7%͒. These parameters set the experimental conditions within which a nanostructuring of the physical properties of GaAs 1−x N x is attainable.

Fabrication of Site‐Controlled Quantum Dots by Spatially Selective Incorporation of Hydrogen in Ga(AsN)/GaAs Heterostructures

“…Hydrogen distributions have been determined by solving the system of partial differential equations that simulate H kinetics in Ga(AsN). [ 21 ] The boundary and initial conditions used in the calculations are set equal to those used experimentally to obtain the nanostructures described in the following: nitrogen concentration x = 1.1%, hydrogen irradiation temperature T H = 200 ° C, hydrogen ion current 30 μ A cm − 2 , and exposure time t = 420 s; see Supporting Information for details. In the N-free GaAs epilayer (panel (a)), a purely Fick-like diffusive motion is found with a H concentration smeared over the forefront.…”

Site-Controlled Quantum Emitters in Dilute Nitrides and their Integration in Photonic Crystal Cavities

“…This is shown in Figure 2, which displays deuterium concentration profiles (symbols) for different nitrogen concentrations (panel a) and TD (panel b), as derived in GaAsN by secondary-ion-mass spectrometry (SIMS) measurements. Simulations (solid lines) that accurately reproduce the data have been obtained by solving a system of differential equations, describing the time evolution of the concentration of free N and D atoms and of the different N-D complexes forming and dissociating in the lattice during the deuteration process [69]. A key point accounting for the D profile is the multiple trapping character of D As extensively investigated in the case of GaAsN, the tuning of the band-gap energy is accompanied by a H-induced tuning of the electron effective mass [39] and gyromagnetic factor [42], which clearly indicates that the entire band structure of the system is profoundly affected by H, and that the attainment of a fine control on H incorporation would provide us with the means to finely tune the electronic properties of the alloy.…”

Hydrogen‐mediated nanostructuring of dilute nitride semiconductors

“…In order to consistently reproduce all the deuterium profiles the only pair of activation energies that fit all data are E a = (1.75 ± 0.03) eV and E b = (2.0 ± 0.1) eV, in accordance with those derived from previous studies 15. The detailed dependence of the two important parameters for D diffusion, namely, the diffusion coefficient and capture radius, on the irradiation temperature and on nitrogen concentration can be found in reference 20.…”

“…The success of our approach heavily relies on the capability of controlling hydrogen–nitrogen interaction at the nanoscale. In order to get information about hydrogen (or deuterium, D) kinetics in GaAsN, we combine secondary ion spectrometry measurements (SIMS) with a diffusion model for H in the presence of multiple trapping processes 18–20. In particular, we develop a powerful method for predicting the 3D H distribution in any GaAsN sample and in the presence of a H‐opaque metallic mask.…”