In this work several structural and chemical properties of self-assembled InAs islands grown on GaAs(001) are studied using surface x-ray scattering with synchrotron radiation. The technique of x-ray diffraction under grazing incidence condition was employed to differentiate coherent and incoherent islands. We used a model of a strained pyramidal island to interpret the x-ray results and correlate size and strain-state of these islands. The degree of GaAs interdiffusion in the islands was inferred from the variation of volume of the unit cell. The Poisson's ratio of the two materials involved establishes a limit of tetragonal distortion for this material. Any variation in this distortion is associated with the presence of Ga inside the islands.

A análise estrutural de materiais experimentou um grande avanço nos últimos anos, associado ao desenvolvimento das técnicas de Microscopia de Varredura por Sonda Mecânica, surgidas na década passada e consolidadas nos anos 90. Trata-se de um enfoque analítico inteiramente original, envolvendo conhecimento e tecnologia multidisciplinar, de amplo espectro de aplicação, devido, principalmente, à resolução em escala nanométrica, à facilidade de operação ao ar, em meio líquido e em vácuo e à possibilidade de grandes ampliações na direção z. Neste artigo, são descritos os princípios básicos das técnicas mais utilizadas, ilustrados através de exemplos de trabalhos realizados pelo grupo do Laboratório de Nanoscopia da Fundação Centro Tecnológico de Minas Gerais - CETEC. São apresentados exemplos obtidos em diversas tipos de materiais, visando mostrar a potencialidade destas novas técnicas de análise nanoestrutural.

During the last few years, the structural analysis of materials has gone through a great advancement which is related to the development of Scanning Probe Microscopy techniques. Originated in the last decade, these techniques were strengthened and spread worldwide during the 90s. They constitute a new methodology of analysis, involving both knowledge and technology from a multitude of different areas. Their large application spectrum is due, mainly, to: large nanometric-scale resolution; capability of operation in air, liquid or in vacuum environments; and the great quantitative magnification in the z direction. In this paper, the basic ideas concerning the most utilized techniques are described. Applications of each technique, evidencing its potentialities in nanostructural analysis, are also illustrated by some examples of works carried out at the Laboratório de Nanoscopia of the Fundação Centro Tecnológico de Minas Gerais - CETEC.