Smallest ever advent calendar made

Fun with electron microscopes –

A group of nanotech specialists in Germany have got into the Christmas spirit by making what they believe is the smallest ever Advent calendar. It would take about five million of the miniature calendars to cover a postage stamp.

PhD student Daniel Neumaier, one of three members of the University of Regensburg’s micro- and nanostructures group that created the calendar, told Chemistry World, ‘We wanted to have a nice picture of Christmas on our home page. We waited until normal business was done for the day in the clean room. Then we went in and did it. We were just having fun.’

The rectangular Advent calendar measures 8.4µm by 12.4µm and is etched onto a semi-conducting gallium arsenide wafer coated with Poly(methyl methacrylate) (PMMA) – used to make Perspex…

Smallest ever advent calendar made – Link.