Differential scanning calorimetry of amorphous silicon (

No abstract

Room-temperature deposited submonolayers of silicon on Si͑001͒ are investigated using STM. The observed structures and the mechanisms leading to their formation are discussed. Isolated ad-dimers in different geometries are described and a kinetic model for their formation is deduced. It is shown how further growth occurs via the formation of 3-atom clusters, which act as nucleation centers for the formation of two types of linear structures. One of the line types is formed in the ͓110͔ direction, and has been observed before. The other is in the ͓310͔ direction. At a coverage of nearly 0.2 ML a kind of random network consisting of segments of the two types of atomic lines is formed. Above 0.2 ML coverage these lines are converted into epitaxial dimer rows. A pathway for this conversion is proposed on the basis of experimental observations.

A translation stage has been developed for generating displacements with nanometer accuracy and a dynamic range of 10 pm. The stage uses piezo stacks as actuators and is equipped with capacitive sensors which are able to measure displacements with subnanometer resolution. Because the measurements are very accurate, the displacement properties of the piezo actuator used in the translation stage can be recorded with high precision. This allows us to investigate the displacement response of the piezo actuator when sinusoidal and triangular voltages are applied to it. These measurements will be used to model the hysteresis behavior of the piezo actuator. It is observed that the branches of the hysteresis curves can be described by a third-order polynome and that the hysteresis curve has point symmetry properties. Also a model is presented for describing the general behavior of a piezo actuator in a translation stage. 8 1995 American Institute of Physics.