Abstract: Described herein is an ion pump system implementing an electronic ratchet mechanism produced by modulating a spatially varying electric potential distribution that can result in a net ionic current and voltage. The ion pumping membrane system includes an ion-permeable layer that can also be integrated with ion-selective membranes. The electric potential distribution within the ion-permeable layer is modulated through external stimuli. When immersed in solution, ions within the ion-permeable layer experience a time varying, spatially asymmetric electric field distribution resulting in ratchet-driven direct ion pumping, which can be used in applications such as desalination.

Abstract: Described herein is an ion pump system implementing an electronic ratchet mechanism produced by modulating a spatially varying electric potential distribution that can result in a net ionic current and voltage. The ion pumping membrane system includes an ion-permeable layer integrated with ion-selective membranes. The electric potential distribution within the ion-permeable layer is modulated through external stimuli. When immersed in solution, ions within the ion-permeable layer experience a time varying, spatially asymmetric electric field distribution resulting in ratchet-driven direction pumping, which can be used in applications such as desalination.

Abstract: A transistor (100), including a planar semiconducting substrate (36), a source (42) formed on the substrate, a first drain (102) formed on the substrate, and a second drain (104) formed on the substrate in a location physically separated from the first drain. At least one gate (38, 40) is formed on the substrate and is configured to selectably apply an electrical potential to the substrate in either a first spatial pattern, which causes a first conductive path (62) to be established within the substrate from the source to the first drain, or a second spatial pattern, which causes a second conductive path to be established within the substrate from the source to the second drain.

Abstract: A transistor (100), including a planar semiconducting substrate (36), a source (42) formed on the substrate, a first drain (102) formed on the substrate, and a second drain (104) formed on the substrate in a location physically separated from the first drain. At least one gate (38, 40) is formed on the substrate and is configured to selectably apply an electrical potential to the substrate in either a first spatial pattern, which causes a first conductive path (62) to be established within the substrate from the source to the first drain, or a second spatial pattern, which causes a second conductive path to be established within the substrate from the source to the second drain.

Abstract: This disclosure provides systems, methods, and apparatus related to a hybrid photo-electrochemical and photo-voltaic cell. In one aspect, device includes a substrate comprising a semiconductor, a transparent conductor disposed on the second surface of the substrate, a photoanode disposed on the transparent conductor, an electrolyte in electrical communication with the photoanode, and an electrode in contact with the electrolyte. The substrate is doped with a first n-type dopant. A first area of a first surface of the substrate is heavily doped with a first p-type dopant. A second area of the first surface of the substrate is heavily doped with a second n-type dopant. The second surface of the substrate is heavily doped with a second p-type dopant. The electrode is in electrical contact with the second area. The first area is in electrical contact with the second area through an electrical load.

Abstract: This disclosure provides systems, methods, and apparatus related to a hybrid photo-electrochemical and photo-voltaic cell. In one aspect, device includes a substrate comprising a semiconductor, a transparent conductor disposed on the second surface of the substrate, a photoanode disposed on the transparent conductor, an electrolyte in electrical communication with the photoanode, and an electrode in contact with the electrolyte. The substrate is doped with a first n-type dopant. A first area of a first surface of the substrate is heavily doped with a first p-type dopant. A second area of the first surface of the substrate is heavily doped with a second n-type dopant. The second surface of the substrate is heavily doped with a second p-type dopant. The electrode is in electrical contact with the second area. The first area is in electrical contact with the second area through an electrical load.

Abstract: A transistor (100), including a planar semiconducting substrate (36), a source (42) formed on the substrate, a first drain (102) formed on the substrate, and a second drain (104) formed on the substrate in a location physically separated from the first drain. At least one gate (38, 40) is formed on the substrate and is configured to selectably apply an electrical potential to the substrate in either a first spatial pattern, which causes a first conductive path (62) to be established within the substrate from the source to the first drain, or a second spatial pattern, which causes a second conductive path to be established within the substrate from the source to the second drain.

Abstract: A monolithic semiconductor solar cell including a semiconductor layer including a plurality of pores, wherein walls of the pores are doped, forming vertical junctions between the walls of the pores and a bulk of the semiconductor, the pores each contain a conductor which is in electrical contact with the walls of the pores, and the conductors of the pores are electrically interconnected to provide an output voltage of the solar cell. A monolithic semiconductor solar cell including a semiconductor layer including a plurality of trenches, wherein walls of the trenches are doped, forming vertical junctions between the walls of the trenches and a bulk of the semiconductor, the trenches each contain a conductor which is in electrical contact with the walls of the trenches, and the conductors of the trenches are electrically interconnected to provide an output voltage of the solar cell. Related apparatus and methods are also described.