Control of the MBE equipment for growth of nano structures
The technique of molecular-beam-epitaxy (MBE) is the most refined for making semiconductor nanostructures. Nowadays, the growth of self-organised nano structures has been intensively investigated. This technique makes it possible the necessary special sample preparation and the in-situ observation of the nanostructures, growing in a self-organising manner. For the sample preparation and its investigation, we need very accurate control of the MBE equipment. In this paper, we present the programable logical controller (PLC) system wich steer our equipment. Here, we show the control of the heating out system of the vacuum chambers, the control of the furnace of the molecular sources and the control of the moving of the shutters.
Automatización de obturadores de sistema de crecimiento por haces moleculares usando arduino mega en una interfaz de Labview
En este trabajo reportamos el desarrollo de un control de obturadores para un sistema de crecimiento por Haces Moleculares (EHM) o del Ingles Molecular Beam Expitaxy (MBE) utilizando una interfaz gráfica de LabView y la plataforma de Arduino Mega para la adquisición de datos. La técnica de epitaxia por haces moleculares permite controlar espesores a escala nanométrica de muy alta calidad cristalina, para la fabricación de dispositivos electrónicos y optoelectrónicos.
Ordering and shape of self-assembled InAs quantum dots on GaAs(001)
Quantitative grazing-incidence small-angle x-ray scattering experiments have been performed on self-assembled InAs quantum dots (QDs) grown by molecular-beam epitaxy. We find pronounced nonspecular diffuse scattering satellite peaks with high diffraction orders, indicating a lateral ordering in the spatial positions of the InAs QDs. The mean-dot–dot distance and correlation lengths of the dot lateral distribution are found to be anisotropic. We observe the sharpest dot distribution in the [110] direction. Additional broad diffraction peaks are observed and associated with dot facet crystal truncation rods of the {111} and {101} facet families. This suggests an octagonal-based dot shape.