Solar Cell
 
A solar cell is a photovoltaic device which converts sunlight into electricity. This specimen is a conventional polycrystalline based Solar Cell, similiar to those which you can buy in local hobby store. At the highest magnification you can see the individual grains of the base material principlly silicon, which has pyramidal protrusions from the surface. These pyramidal structures are coated with thin layers of material increase its efficiency. At low magnfication you can see the electrically conductive pathways between the active regions of the silicon grains.