TECHNOLOGY FOCUS - ELECTRONICS - Preferred Method: In the method, a first portion of the graded-composition layer (126) comprises silicon germanium and is disposed between the substrate and the isolation diode (128) and a second portion of the graded-composition layer comprises silicon germanium and is disposed between the isolation diode and the first cell, where the first portion grading from an initial germanium content to an intermediate germanium content is larger than the initial germanium content and the second portion grading from approximately the intermediate germanium content to a final germanium content is larger than the intermediate germanium content. In the method: the step of forming many discrete solar cells comprise, for each solar cell, forming a first contact to the cap layer (150) and forming a second contact to a layer disposed beneath the first cell, where each of the first and second contacts are formed over the top surface of the substrate; the step of forming the first and second contacts comprises substantially simultaneously reacting a metal with a portion of the cap layer and a portion of the layer disposed beneath the first cell, where the first contact comprises a silicide of the metal and the second contact comprises a germanosilicide of the metal; and the step of forming the bypass diodes comprises, for each bypass diode, forming a first contact to a top surface of the first cell and a second contact to a layer disposed beneath the first cell, where each of the first and second contacts are formed over the top surface of the substrate, where forming the first and second contacts comprises substantially simultaneously reacting a metal with a portion of the first cell and a portion of the layer disposed beneath the first cell and each of the first and second contacts comprise germanosilicide of the metal, and the first contact covers substantially all of a top surface of the first cell of the bypass diode, thus substantially preventing solar illumination. The method further comprises: forming at least one additional series string of discrete solar cells on the substrate, and electrically connecting the series string and at least one additional series string in parallel; forming over the top surface of the substrate and electrically connecting to the series string, circuitry for maximum power-point tracking, where the circuitry comprises a direct current/ direct current converter; and electrically connecting the circuitry to a charge-storage element not disposed over the top surface of the substrate. In the method: forming the series string comprises forming interconnection circuitry on the substrate between each of the plurality of discrete solar cells, where the interconnection circuitry between at least two of the discrete solar cells comprises a switching element enabling reconfiguration of the electrical connection between at least two discrete solar cells, or the interconnection circuitry between each of the discrete solar cells comprises a switching element enabling reconfiguration of all of the electrical connections between the discrete solar cells; and the charge-storage element is disposed under a bottom surface of the substrate opposite the top surface. Preferred Components: The structure comprises: an isolation diode disposed beneath the first cell, where the isolation diode comprises a p-n junction or a p-i-n junction having a polarity opposite a polarity of the first cell; a graded-composition layer disposed beneath the first cell, where the graded-composition layer relieves at least a portion of a lattice-mismatch strain between the substrate and the first cell; and a constant-composition having silicon germanium layer disposed between the first and second portions of the graded-composition layer, where the constant-composition layer having germanium content is approximately equal to the intermediate germanium content; and a silicon cap layer disposed over the second cells. The isolation diode comprises silicon germanium having a bandgap smaller than a bandgap of the first cell. EXAMPLE - No suitable example given.