Abstract: Methods and apparatuses for a dual heterojunction multijunction solar cell are disclosed. A method in accordance with the present invention comprises growing a base material for a solar cell, growing at least one dual heterojunction on the base material, and growing an emitter on the at least one dual heterojunction. An apparatus in acccordance with the present invention comprises a substrate, and a first subcell, coupled to the substrate, wherein the first subcell comprises a base region, coupled to the substrate, an emitter region, and at least one dual heterojunction, coupled between the base region and the emitter region, wherein the at least one dual heterojunction has a lower bandgap than the emitter region.

Abstract: An apparatus and method for making a solar cell assembly. An apparatus in accordance with the present invention comprises a substrate, at least a first solar cell, coupled to a first side of the substrate, the first side of the substrate to be exposed to light such that the at least first solar cell generates a current when exposed to the light, and a bypass diode, formed on a second side of the substrate, the second side of the substrate being substantially opposite the first side of the substrate, such that the bypass diode is monolithically integrated with the at least first solar cell.

Abstract: A metamorphic avalanche photodetector includes a substrate, and an active structure supported on the substrate. The active structure has a metamorphic absorption structure that absorbs light and responsively produces primary charge carriers, and an avalanche multiplication structure that receives the primary charge carriers from the metamorphic absorption structure and responsively produces secondary charge carriers. An output electrical contact is in electrical communication with the active structure to collect at least some of the secondary charge carriers. A buffer layer lies between the substrate and the active structure, between the active structure and the output electrical contact, or between the metamorphic absorption structure and the avalanche multiplication structure. A lattice parameter of the buffer layer varies with position through a thickness of the buffer layer.

Abstract: Methods and apparatus are provided for configuring a Schottky diode with reduced reverse leakage current. The apparatus comprises a dielectric layer interposed between a Schottky metal layer and a Schottky semiconductor layer. The dielectric layer is patterned to allow a limited amount of direct contact between the metal layer and the semiconductor layer, thereby controlling the size and configuration of the Schottky diode active area. Limiting the amount of active diode area can reduce the probability of leakage current due to localized shunts. Moreover, the dielectric layer can also be configured to inhibit diffusion from the metal layer to the semiconductor layer. Accordingly, the reverse leakage current of a Schottky diode with dielectric isolation is typically lower than that of a similar diode with no dielectric layer.