15 August 2012
Picture a solar cell and chances are it will look like a flat panel. The demand for photovoltaics that can conform to a certain size, shape, or structure, however, is increasing. Microsystems Enabled Photovoltaics (MEPV) from Sandia National Laboratories, Albuquerque, N.M., represent a move toward miniaturized crystalline silicon and crystalline gallium-arsenide (GaAs) solar cells that can fit within the intricate shapes and contours of various objects.
To fabricate these cells, Sandia’s MEPV team have combined microfabrication techniques from several microsystem technologies. The process flow uses standard equipment and standard wafer thicknesses and allows all high-temperature processing to be performed prior to cell release. This means that for both silicon and GaAs cells are backside contacted, which enables the fabrication of uniform, aesthetically pleasing front sides without electrical lines. In addition, the remaining post-release wafer can be reprocessed and reused, resulting in a substantial increase in the number of watts generated per gram of semiconductor material.
With dimensions as small as 100-μm wide and 1-μm thick, these PV building blocks can be installed in flexible, moldable, or flat-plate formats in sizes that conform to the shapes and contours of natural terrain, large structures, vehicles, and mobile electronics.
Sandia National Laboratories