Systems and methods of three-terminal tandem solar cells are described. Three-terminal metal electrodes can be formed to contact subcells of the tandem solar cell. The three-terminal tandem cell can improve the device efficiency to at least 30%.

A solar cell apparatus 100 and a method for forming said solar cell apparatus 100, comprising a substrate 101, a n-type transparent conductive oxide (TCO) layer 102 deposited atop said substrate 101, a p-i-n structure 200 that includes a p-type layer 103, an i-type layer 104, a n-type layer 105, a metal back layer 106 deposited atop said n-type layer 105 of the p-i-n structure 200. The n-type layer 105 comprises n-type donors 115 including phosphorus atoms. The n-type donors 115 include oxygen atoms at an atomic concentration comprised between 5% and 25% of the overall atomic composition of the n-type layer 105.

A solar cell apparatus 100 and a method for forming said solar cell apparatus 100, comprising a substrate 101, a n-type transparent conductive oxide (TCO) layer 102 deposited atop said substrate 101, a p-i-n structure 200 that includes a p-type layer 103, an i-type layer 104, a n-type layer 105, a metal back layer 106 deposited atop said n-type layer 105 of the p-i-n structure 200. The n-type layer 105 comprises n-type donors 115 including phosphorus atoms. The n-type donors 115 include oxygen atoms at an atomic concentration comprised between 5% and 25% of the overall atomic composition of the n-type layer 105.

A growth structure having a lattice transition (or graded buffer) or an engineered growth structure with a desired lattice constant, different from a lattice constant of conventional substrates like GaAs, Si, Ge, InP, under a release layer or an etch stop layer is used as a seed crystal for growing optoelectronic devices. The optoelectronic device can be a photovoltaic device having one or more subcells (e.g., lattice-matched or lattice-mismatched subcells). The release layer can be removed using different processes to separate the optoelectronic device from the growth structure, which may be reused, or from the engineered growth structure. When using the etch stop layer, the growth structure or the engineered growth structure may be grinded or etched away. The engineered growth structure may be made from a layer transfer process between two wafers or from a ternary and/or a quaternary material. Methods for making the optoelectronic device are also described.

A growth structure having a lattice transition (or graded buffer) or an engineered growth structure with a desired lattice constant, different from a lattice constant of conventional substrates like GaAs, Si, Ge, InP, under a release layer or an etch stop layer is used as a seed crystal for growing optoelectronic devices. The optoelectronic device can be a photovoltaic device having one or more subcells (e.g., lattice-matched or lattice-mismatched subcells). The release layer can be removed using different processes to separate the optoelectronic device from the growth structure, which may be reused, or from the engineered growth structure. When using the etch stop layer, the growth structure or the engineered growth structure may be grinded or etched away. The engineered growth structure may be made from a layer transfer process between two wafers or from a ternary and/or a quaternary material. Methods for making the optoelectronic device are also described.

Photovoltaic devices such as solar cells having one or more field-effect hole or electron inversion/accumulation layers as contact regions are configured such that the electric field required for charge inversion and/or accumulation is provided by the output voltage of the photovoltaic device or that of an integrated solar cell unit. In some embodiments, a power source may be connected between a gate electrode and a contact region on the opposite side of photovoltaic device. In other embodiments, the photovoltaic device or integrated unit is self-powering.

Photovoltaic devices such as solar cells having one or more field-effect hole or electron inversion/accumulation layers as contact regions are configured such that the electric field required for charge inversion and/or accumulation is provided by the output voltage of the photovoltaic device or that of an integrated solar cell unit. In some embodiments, a power source may be connected between a gate electrode and a contact region on the opposite side of photovoltaic device. In other embodiments, the photovoltaic device or integrated unit is self-powering.

A semiconductor device and method for fabricating same is disclosed. Embodiments are directed to a semiconductor device and fabrication of same which include a polycrystalline or amorphous substrate. An electrically conductive Ion Beam-Assisted Deposition (IBAD) template layer is positioned above the substrate. At least one electrically conductive hetero-epitaxial buffer layer is positioned above the IBAD template layer. The at least one buffer layer has a resistivity of less than 100 μΩcm. The semiconductor device and method foster the use of bottom electrodes thereby avoiding complex and expensive lithography processes.

A semiconductor device and method for fabricating same is disclosed. Embodiments are directed to a semiconductor device and fabrication of same which include a polycrystalline or amorphous substrate. An electrically conductive Ion Beam-Assisted Deposition (IBAD) template layer is positioned above the substrate. At least one electrically conductive hetero-epitaxial buffer layer is positioned above the IBAD template layer. The at least one buffer layer has a resistivity of less than 100 μΩcm. The semiconductor device and method foster the use of bottom electrodes thereby avoiding complex and expensive lithography processes.

A method for manufacturing a stacked thin film, includes forming a photoelectric conversion layer on a first transparent electrode by sputtering using a target mainly composed of copper in an oxygen containing atmosphere. An oxygen partial pressure of the sputtering is in a range of 0.01 [Pa] or more and 4.8 [Pa] or less, and 0.24d [Pa] or more and 2.4d [Pa] or less when a deposition rate is d [m/min], in formation of the photoelectric conversion layer. A sputtering temperature is 300 C. or more and 600 C. or less, in formation of the photoelectric conversion layer.