TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Solar Cell: The top of the first active region is coalesced with the top of the second active region to form the front region. The first active region, the second active region, and the front region are all either p-doped or n-doped. The first active region and the second active region are not doped and the front region is co-doped with both an n-type dopant and a p-type dopant. The first active region and the second active region each comprise nanostructures. The first active region and the second active region are also electrically isolated from each other between the substrate and the front region. The first active region and the second active region are each formed from a group III-V compound semiconductor. The n-doped region of the substrate and the p-doped region of the substrate create an electric field across the first active region and the second active region, the electric field sweeps charge carriers that are created from photon absorption in the active regions upwards in one of the active regions and downwards in the other active region, the charge carriers pass through the front region. The solar cell comprises: (a) a substrate having a front side and a back side, where the substrate has first regions that are n-type conductivity and second regions that are p-type conductivity, where each of the regions of one of the conductivity types is adjacent to one of the regions of the other conductivity types; (b) first active regions, where each active region of the first active regions is over one of the n-type regions and has a top; (c) second active regions, where each active region of the second active regions is over one of the p-type regions and has a top; (d) an optically transparent region that connects the tops of active regions of the first and second active regions to allow charge transfer; (e) first conductive contacts exposed on the back side of the substrate, each contact of the first contacts is proximate to one of the n-type regions; and (f) second conductive contacts exposed on the back side of the substrate, each contact of the second contacts is proximate to one of the p-type regions. The first active regions are lightly n-doped, the second active regions are lightly n-doped, and the optically transparent region is lightly n-doped, moderately n-doped, or heavily n-doped. The first active regions are lightly p-doped, the second active regions are lightly p-doped, and the optically transparent region is lightly p-doped, moderately p-doped, or heavily p-doped. Current due to charge carriers that are created from photon absorption in the first and second active regions travels upwards in one of the first active regions, through a portion of the optically transparent region, and downwards in an adjacent second active region. One of the first active regions and an adjacent one of the second active regions forms part of a micro solar cell, and where: (i) one of the first contacts are electrically connected to adjacent one of the second contacts to connect micro solar cells in series; or (ii) where at least two of the first contacts are electrically connected together, and at least two of the second contacts are electrically connected together to form a parallel connection of a micro solar cell. Preferred Method: Forming the front region includes growing the first active region and the second active region so that they are coalesced. Forming the first active region, forming the second active region, and forming the front region include incorporating n-doping into the first active region and the second active region, and co-doping the front region with both n-doping and p-doping. It also includes incorporating either p-doping or n-doping into each of the first active region, the second active region, and the front region. Forming the first active region and forming the second active region includes growing nanostructures. It also includes depositing a material and etching the material to form the first active region and the second active region.