Apparatuses for generating electrical energy

An electrical energy generation apparatus, comprising:

• a first plate and a second plate disposed apart from each other;
• a first electrode on the first plate;
• a plurality of first nano wires on the first electrode and formed of a semiconductor material;
• a plurality of semiconductor layers forming a p-n junction with the first nano wires, respectively, wherein the plurality of semiconductor layers cover surfaces of the first nano wires;
• a plurality of second electrodes covering surfaces of the semiconductor layers;
• a third electrode on a bottom surface of the second plate;
• and
• a plurality of second nano wires on a bottom surface of the third electrode, wherein the plurality of second nano wires form a Schottky contact with the first electrode.