We report on the fabrication and characterisation of Mo/Au bilayers which are intended to be used as high resolution cryogenic imaging spectrometers for next generation of X-ray Astrophysical observatories in space. Mo/Au bilayers have been deposited by sputtering at room temperature on Si3N4 bulk and membranes. The composition of the bilayers as well as their interfaces have been characterised by Rutherford Backscattering Spectroscopy (RBS). Results indicate absence of interdiffusion. Further structural characterization has been performed by X-ray diffraction and Atomic Force Microscopy. The transition temperature T c of the Mo/Au bilayers has been tuned by changing the Au layer thickness. Very sharp superconducting transitions have been observed with transition widths as small as 0.3 mK. These films look therefore extremely promising for the intended detectors, as well as for other applications in materials science and nanotechnology.

This work has been carried out with financial support from the Spanish MEC (projects ESP2004-21934-E, MAT2005-02454 and PN-ESP2006-13608-C02). Three of the Authors (R.G.A., J.S. and M.P.B.) would like to thank MEC and the Aragon Government for the Juan de la Cierva, Ramon y Cajal and predoctoral financial support, respectively.We also want to thank R. Alvaro and P. Prieto for the lithography and wet etching processes.

From the issue entitled "Proceedings of the 12th International Workshop on Low Temperature Dectectors (LTD12)- Part I"

Peer reviewed