NOVELTY - A solar cell (200) comprises a controlled atmospheric annealed single crystal aluminum antimonide (AlSb) substrate material, which is utilized as an active host layer; and solid-solution semiconductor material(s) coupled to the annealed single crystal AlSb active host layer, where each of the solid-solution semiconductor materials further comprises a lattice parameter so as to produce a lattice-matched configuration. The controlled atmospheric annealed host layer comprises n-type host layer (204), or p-type host layer (202).    USE - As a solar cell such as heterojunction, homo-junction, and multi-junction solar cells including quantum well solar cell and quantum well solar cell (claimed) for converting solar energy into electrical power useful in terrestrial solar cell and concentrator solar cell applications, both terrestrially and in space.    ADVANTAGE - The solar cell includes controlled atmospherically annealed high purity AlSb single crystals which efficiently couples the sun's energy distribution. Because AlSb has energy bandgap slightly higher than GaAs, AlSb has a good terrestrial solar spectrum power match, and in space, the power match of AlSb to the solar spectrum is very good, representing, near maximum solar energy conversion efficiency. The AlSb concentrator solar cell, due to its higher energy bandgap, has the potential to operate at higher solar conversion efficiency than a GaAs concentrator solar cell. Because of its indirect energy bandgap and the potential to have free carrier recombination loses on the order of Si, high temperature operation of AlSb reduces the amount of solar cell surface required of Si to produce an equivalent power output.    DETAILED DESCRIPTION - A solar cell (200) comprises a controlled atmospheric annealed single crystal aluminum antimonide (AlSb) substrate material, which is utilized as an active host layer; and solid-solution semiconductor material(s) coupled to the annealed single crystal AlSb active host layer, where each of the solid-solution semiconductor materials further comprises a lattice parameter so as to produce a lattice-matched configuration. The controlled atmospheric annealed host layer comprises n-type host layer (204), or p-type host layer (202). The solar cell further comprises at least one arrangement selected from antireflection coatings, buffer layers, ohmic contacts (210), tunnel junctions, and passivation layers. INDEPENDENT CLAIMS are included for the following:    (1) producing a homojunction solar cell involving providing high-purity single crystal ingots of AlSb; forming wafers from the high-purity single crystal ingots; providing controlled atmospheric annealing of the single crystal wafers to adjust the stoichiometry; positioning dopants in the wafers so as to form predetermined p-n junctions; surface passivating the single crystal wafers; forming contacts on predetermined regions of the solar cell; and utilizing antireflection technologies and packaging to provide a final product; and    (2) producing the solar cell involving providing a controlled atmospheric annealed single crystal AlSb substrate, which is configured as an active host layer; and coupling solid-solution semiconductor materials with the controlled atmospheric annealed single crystal AlSb active host layer.    DESCRIPTION OF DRAWING(S) - The figure shows a p-n homo-junction solar cell.    homo-junction solar cell (200)    p-type AlSb material (202)    n-type AlSb material (204)    ohmic contact stripe (208)    ohmic contacts. (210)