Integrated solar energy harvesting and storage

To explore integrated solar energy harvesting as a power source for low power systems such as wireless sensor nodes, an array of energy scavenging photodiodes based on a passive-pixel architecture for imagers and have been fabricated together with storage capacitors implemented using on-chip interconnect in a 0.35 μm CMOS logic process. Integrated vertical plate capacitors enable dense energy storage without limiting optical efficiency. Measurements show 225 μW/mm2 output power generated by a light intensity of 20k LUX.