Abstract: Evolution and coarsening behaviour of self-assembled nano-dots fabricated on an InP surface by 3 keV Ar ion sputtering have been studied in conjunction with the structural modifications at the surface. The dots have been produced in off-normal geometry but in the absence of rotation. For small sputtering durations, the dots coarsen and agglomerate, up to a critical time tc, while the surface roughens and experiences a tensile stress. A relaxation in this stress is observed after the surface becomes amorphized at tc, beyond which an inverse coarsening, fragmentation of dots and a smoothened surface are observed.

Abstract: Structural modifications in InP(111) due to 1.5 MeV implantation of Sb have been characterized using first-order and second-order Raman spectroscopy. With both longitudinal optical (LO) and transverse optical (TO) modes allowed for InP(111), we have investigated the evolution of both these modes as a function of fluence. Investigations of both the first and second-order Raman modes indicate the presence of tensile stress in the lattice after implantation, which increases with fluence. Results show a coexistence of nanocrystalline InP regions and amorphous zones in the lattice. Consequently phonon confinement is observed and phonon confinement model (PCM) has been applied here to estimate the coherence length and the size of nanocrystalline zones in InP lattice after implantation. Nanocrystalline zones as small as 35 Ã… have been observed here. A LO phonon-plasmon coupled mode, due to the charge layer in the vicinity of the surface, has also been observed. This coupled mode becomes sharper and more intense with increasing fluence. For high fluences, crystalline to amorphous phase transition has also been observed. First and second-order LO modes have been utilized to estimate the electron-phonon coupling strengths. The coupling strength is observed to decrease as the nanocrystalline zones

Abstract: We have studied the surface modifications as well as the surface roughness of the InP(111) surfaces after 1.5 MeV Sb ion implantations. A scanning probe microscope has been utilized to investigate the ion-implanted InP(111) surfaces. We observe the formation of nanoscale defect structures on the InP surface. The density, height, and size of the nanostructures have been investigated here as a function of ion fluence. The rms surface roughness, of the ion implanted InP surfaces, has also been investigated. Raman-scattering results demonstrate that at the critical fluence, where the decrease in surface roughness occurs, the InP lattice becomes amorphous