A method for producing an electronic device having a drive circuit including a solar cell structure, the method including the steps of: having a first wafer having solar cell structures on a starting substrate and a second wafer having drive circuits formed, so that either one of the first wafer or the second wafer has a plurality of independent diode circuits and capacitor-function laminated portions; obtaining a bonded wafer by bonding so that the solar cell structures, the diode circuits, the capacitor-function laminated portions, and the drive circuits are superimposed; wiring; and dicing the bonded wafer; thus creating a method for producing an electronic device including a drive circuit, a solar cell structure, and a capacitor-function portion in one chip and having a suppressed production cost; and such an electronic device.

A stack-type III-V multijunction solar cell having an upper side and an underside, which includes a substrate layer formed on the underside and a first subcell having a first bandgap on the substrate layer or comprising the substrate layer. A second subcell has a second bandgap and is arranged above the first subcell. A tunnel diode is formed between the first subcell and the second subcell. A finger-shaped first metallic contact region is formed on the upper side. A second metallic contact region is formed over a wide area on the underside. The first contact region comprises multiple metal layers and has a first metal layer comprising silver in a vicinity of the surface and has a titanium layer designed as the uppermost metal layer above the first metal layer to reduce reflection on the upper side. The titanium layer has a thickness of more than 5 nm.

A stack-type III-V multijunction solar cell having an upper side and an underside, which includes a substrate layer formed on the underside and a first subcell having a first bandgap on the substrate layer or comprising the substrate layer. A second subcell has a second bandgap and is arranged above the first subcell. A tunnel diode is formed between the first subcell and the second subcell. A finger-shaped first metallic contact region is formed on the upper side. A second metallic contact region is formed over a wide area on the underside. The first contact region comprises multiple metal layers and has a first metal layer comprising silver in a vicinity of the surface and has a titanium layer designed as the uppermost metal layer above the first metal layer to reduce reflection on the upper side. The titanium layer has a thickness of more than 5 nm.

A multijunction solar cell including an upper first solar subcell having an emitter and base layers forming a photoelectric junction; a second solar subcell disposed under and adjacent to the upper first solar subcell, and having an emitter and base layers forming a photoelectric junction; and a third solar subcell disposed under and adjacent to the second solar subcell and having an emitter and base layers forming a photoelectric junction; wherein at least one of the base and emitter layers of at least a particular solar subcell from among the upper first solar subcell, the second solar subcell, and the third solar subcell has a graded band gap throughout at least a portion of thickness of its active layer adjacent to the photoelectric junction and being in a range of 20 to 300 MeV less than a band gap in the active layer in both the emitter layer and the base layer spaced away from the photoelectric junction.

A multijunction solar cell including an upper first solar subcell having an emitter and base layers forming a photoelectric junction; a second solar subcell disposed under and adjacent to the upper first solar subcell, and having an emitter and base layers forming a photoelectric junction; and a third solar subcell disposed under and adjacent to the second solar subcell and having an emitter and base layers forming a photoelectric junction; wherein at least one of the base and emitter layers of at least a particular solar subcell from among the upper first solar subcell, the second solar subcell, and the third solar subcell has a graded band gap throughout at least a portion of thickness of its active layer adjacent to the photoelectric junction and being in a range of 20 to 300 MeV less than a band gap in the active layer in both the emitter layer and the base layer spaced away from the photoelectric junction.

A compound solar battery according to the present invention is provided with a laminated film 2 including: a reflection layer 20 formed of an AlGaAs layer; a front surface-side light absorption layer 10 formed between a surface electrode 1 and the reflection layer 20; and a back surface-side light absorption layer 30 formed between the reflection layer 20 and a substrate 3. The reflection layer 20 is formed of a front surface-side reflection layer 20u and a back surface-side reflection layer 20d. A Al content ratio in the front surface-side reflection layer 20u is set to be greater than that in the back surface-side reflection layer 20d. In the back surface-side light absorption layer 30, a first InGaP layer 31, a first GaAs layer 32, a second InGaP layer 33, a second GaAs layer 34, and a third InGaP layer 35 is formed by laminating from the substrate 3 side, and a film thickness of the second GaAs layer 34 is set to be larger than that of the first GaAs layer 32.

A compound solar battery according to the present invention is provided with a laminated film 2 including: a reflection layer 20 formed of an AlGaAs layer; a front surface-side light absorption layer 10 formed between a surface electrode 1 and the reflection layer 20; and a back surface-side light absorption layer 30 formed between the reflection layer 20 and a substrate 3. The reflection layer 20 is formed of a front surface-side reflection layer 20u and a back surface-side reflection layer 20d. A Al content ratio in the front surface-side reflection layer 20u is set to be greater than that in the back surface-side reflection layer 20d. In the back surface-side light absorption layer 30, a first InGaP layer 31, a first GaAs layer 32, a second InGaP layer 33, a second GaAs layer 34, and a third InGaP layer 35 is formed by laminating from the substrate 3 side, and a film thickness of the second GaAs layer 34 is set to be larger than that of the first GaAs layer 32.

A panel including at least one solar cell having a cell comprised of gallium arsenide (GaAs) or indium gallium arsenide (InGaAs) with a back surface field (BSF) comprised of aluminum gallium arsenide (AlGaAs) or indium aluminum gallium arsenide (InAlGaAs) p-type doped for enhanced operation of the solar cell at temperatures less than 50 C. In one example, the back surface field comprises Al.sub.xGa.sub.1-xAs or In.sub.0.01Al.sub.xGa.sub.1-xAs, wherein x is less than about 0.8, for example, 0.2. The back surface field may be p-type doped with zinc (Zn) or carbon (C).

A panel including at least one solar cell having a cell comprised of gallium arsenide (GaAs) or indium gallium arsenide (InGaAs) with a back surface field (BSF) comprised of aluminum gallium arsenide (AlGaAs) or indium aluminum gallium arsenide (InAlGaAs) p-type doped for enhanced operation of the solar cell at temperatures less than 50 C. In one example, the back surface field comprises Al.sub.xGa.sub.1-xAs or In.sub.0.01Al.sub.xGa.sub.1-xAs, wherein x is less than about 0.8, for example, 0.2. The back surface field may be p-type doped with zinc (Zn) or carbon (C).

Photovoltaic cells including a first group-IV subcell including an n-type emitter layer comprising a first group-IV material selected from a first group consisting of Ge, SiGe and SiGeSn, and a second layer comprising a second group-IV material, the second group-IV material being different from the first group-IV material, and the n-type emitter layer being the primary photoabsorber of the first group-IV subcell. A p-n junction of the first group-IV subcell is formed at a heterojunction of the n-type emitter layer and second layer. The photovoltaic cell also includes a tunnel junction, and a second group-IV subcell, the tunnel junction interconnecting the first group IV subcell to the second group-IV subcell, the first group IV subcell and the second group IV subcell being a lowest two subcells of the photovoltaic cell, the first group IV subcell being between the second group-IV subcell and a plurality of HI-V subcells.