An apparatus, system, and method are provided for a lateral two-terminal nanotube device configured to capture and generate energy, to store electrical energy, and to integrate these functions with power management circuitry. The lateral nanotube device can include a substrate, an anodic oxide material disposed on the substrate, and a column disposed in the anodic oxide material extending from one distal end of the anodic oxide material to another end of the anodic oxide material. The lateral nanotube device further can include a first material disposed within the column, and a second material disposed within the column. The first material fills a distal end of the column and gradiently decreases towards another distal end of the column along inner walls of the column. The second material fills the another distal end of the column and gradiently decreases towards the distal end of the column within the first material.