Atomic layer epitaxy and structural characterization of InP and InAs/InP heterostructures

We report the growth and structural properties of InP, InAs/InP strained single quantum wells and short-period InAs/InP strained layer superlattices by atomic layer epitaxy. A self-limiting growth close to 1 monolayer/cycle has been obtained for InP and for InAs with low substrate temperatures between 350 and 360 °C. The samples were grown on InP (001) substrates and characterized by high resolution x-ray diffraction, grazing-incidence x-ray reflectometry, and Raman spectroscopy. The interference of x-ray wave fields in the grown structures observed by both types of x-ray measurements can be used to measure nondestructively the thickness of the deposited films with relatively high precision. High resolution x-ray diffraction and grazing-incidence x-ray reflectometry of the InAs/InP superlattices confirm the periodicity of the structures in agreement with theoretical predictions. Raman spectroscopy shows doublets of folded acoustic modes as well as InAs-like and InP-like confined longitudinal optical phonons in the InAs/InP superlattices. Results indicate that, despite the 3.2% lattice mismatch, atomic layer epitaxy is a powerful method for fabricating highly strained structures with atomically controlled heterointerfaces.