Laser writing on metal-silicon bilayers for optical storage. I. Optical properties

Various bilayer structures consisting of metal and silicon were investigated as possible candidates for the optical recording medium. The silicon-on-metal bilayers offer tunability with a reasonable thickness of Si in the visible spectrum with a typical reflectivity less than 5%. Of the two possible writing processes, the low-power process of silicide formation has a threshold power of 30 mW for a Rh-Si bilayer which provides a reflectivity change in excess of 40%. The absence of raised rims around the written spots offers a smooth morphology that is compatible with encapsulation.