Phonon Characteristics of Gas-Source Molecular Beam Epitaxy-Grown InAs 1−x N x /InP (001) with Identification of Si, Mg and C Impurities in InAs and InN

The lattice dynamical properties of dilute InAs 1−x N x /InP (001) epilayers (0 ≤ x ≤ 0.03) grown by gas-source molecular beam epitaxy were carefully studied experimentally and theoretically. A high-resolution Brüker IFS 120 v/S spectrometer was employed to measure the room-temperature infrared reflectivity (IRR) spectra at near-normal incidence (θ i = 0). The results in the frequency range of 180–500 cm −1 revealed accurate values of the characteristic In-As-like and In-N-like vibrational modes. For InAs 1−x N x alloys, a classical “Drude–Lorentz” model was constructed to obtain the dielectric functions ε ~ ω in the far IR regions by incorporating InAs-like and InN-like transverse optical ω T O modes. Longitudinal optical ω L O phonons were achieved from the imaginary parts of the simulated dielectric loss functions. The theoretical results of IRR spectra for InAs 1−x N x /InP (001) epilayers using a multi-layer optics methodology provided a very good agreement with the experimental data. At oblique incidence (θ i ≠ 0), our study of s- and p-polarized reflectance (R s,p (ω)) and transmission (T s,p (ω)) spectra allowed the simultaneous perception of the ω T O and ω L O phonons of the InAs, InN and InAs 0.97 N 0.03 layers. Based on the average t-matrix Green’s function theory, the results of local vibrational modes for light S i I n + donors and S i A s − , C A s − acceptors in InAs were found in good agreement with the existing Raman scattering and infrared spectroscopy data. I n I n N , however, the method predicted an in-band mode for the M g I n − acceptor while projecting an impurity mode of the S i I n + ...