Atomic ordering in (InGa)(AsN) quantum wells: An In K-edge X-ray absorption investigation

摘要

(InGa)(AsN) quantum wells are particularly interesting for applications in fiber optics based communications, since they permit to make lasers with emission at 1.3 and 1.55 μm, with good temperature stability. The aim of this work is to study the local environment of In by means of X-ray absorption fine structure. In particular, the site ordering around In will be investigated in order to understand the structural origin of the non-linear optical and electronic proprieties which characterize this alloy. Despite the low N concentration (≤5.2%) a significant contribution of In-N bonds to the signal is detected. The data provide evidence of a preferential distribution of N atoms around indium, as recently predicted via Monte Carlo simulations. Hydrogenation further enhances the increase in the number of In―N over In―As bonds.