Cathodoluminescence and transmission electron microscopy study of island formation on InAs/InP QW structures during growth interruptions

摘要

A study on the effect of growth interruptions on InAs/InP strained quantum wells (QW) by cathodoluminescence (CL) at helium temperature and transmission electron microscopy (TEM) is reported. The samples are grown by chemical beam epitaxy (CBE) with and without growth interruptions of 15s at the second interface of the InAs-SQW. Previous photoluminescence measurements showed the formation of InAs large range roughness and/or islands up to 8-monolayers-thick during the interruption. To clarify the structure of the thickness fluctuation TEM and CL observations are performed. QW-islands are revealed by TEM planar view observations. The localized CL spectra, in concordance with the TEM observations, demonstrate that no InAs QWs are present between the island. Only some isolated InAs islands appear in the samples without growth interruption.