Abstract: A method for fabricating a display device that easily achieves higher resolution is provided. A display device having both high display quality and high resolution is provided. A first EL film is formed over a first pixel electrode and a second pixel electrode; a first sacrificial film is formed to cover the first EL film; the first sacrificial film and the first EL film are etched to expose the second pixel electrode and to form a first EL layer over the first pixel electrode and a first sacrificial layer over the first EL layer; and the first sacrificial layer is removed. The first EL film and the second EL film are etched by dry etching, and the first sacrificial layer is removed by wet etching.

Abstract: A semiconductor device including a transistor with high on-state current and a fabrication method thereof are provided. A semiconductor device having favorable electrical characteristics and a fabrication method thereof are provided. The semiconductor device includes a substrate, an island-shaped insulating layer over the substrate, and a transistor over the substrate and the insulating layer. The transistor includes a gate electrode, a gate insulating layer, a semiconductor layer, and a pair of conductive layers. One of the pair of the conductive layers includes a region overlapping with the insulating layer, and the other of the pair of the conductive layers includes a region not overlapping with the insulating layer. The level of a top surface of the other of the pair of the conductive layers is lower than the level of a top surface of the one of the pair of the conductive layers. Each of the pair of the conductive layers is in contact with the semiconductor layer.

Abstract: A highly reliable electrode for a lithium-ion secondary battery is provided. A highly reliable lithium-ion secondary battery is also provided using the electrode for a lithium-ion secondary battery. The electrode for a lithium-ion secondary battery includes a current collector and an active material layer. The active material layer includes an active material, graphene, and polyimide. The active material includes a plurality of nanowires each of which grows with a silicon particle used as a nucleus and extends in one direction into a fine needle. The graphene includes a region in contact with the plurality of nanowires, and polyimide includes a region in contact with the graphene. The lithium-ion secondary battery uses the electrode as a negative electrode.

Abstract: A power storage device with high capacity is provided. Alternatively, a power storage device with excellent cycle characteristics is provided. Alternatively, a power storage device with high charge and discharge efficiency is provided. Alternatively, a power storage device with a long lifetime is provided. A negative electrode active material includes a first region and a second region. The first region includes at least one element selected from Si, Mg, Ca, Ga, Al, Ge, Sn, Pb, Sb, Bi, Ag, Zn, Cd, As, Hg, and In. The second region includes oxygen and the same element as the one included in the first region. The crystallite size of the element included in the first region is larger than or equal to 1 nm and smaller than or equal to 10 nm.

Abstract: A power storage device with high capacity is provided. A power storage device with high energy density is provided. A highly reliable power storage device is provided. A long-life power storage device is provided. An electrode with high capacity is provided. An electrode with high energy density is provided. A highly reliable electrode is provided. Such a power storage device includes a first electrode and a second electrode. The first electrode includes a first current collector and a first active material layer. The first active material layer includes active material particles, spaces provided on the periphery of the active material particles, graphene, and a binder. The active material particles are silicon. The active material particles and the spaces are surrounded by the graphene and the binder.

Abstract: A power storage device with high capacity is provided. A power storage device with high energy density is provided. A highly reliable power storage device is provided. A long-life power storage device is provided. An electrode with high capacity is provided. An electrode with high energy density is provided. A highly reliable electrode is provided. Such a power storage device includes a first electrode and a second electrode. The first electrode includes a first current collector and a first active material layer. The first active material layer includes active material particles, spaces provided on the periphery of the active material particles, graphene, and a binder. The active material particles are silicon. The active material particles and the spaces are surrounded by the graphene and the binder.

Abstract: A highly reliable electrode for a lithium-ion secondary battery is provided. A highly reliable lithium-ion secondary battery is also provided using the electrode for a lithium-ion secondary battery. The electrode for a lithium-ion secondary battery includes a current collector and an active material layer. The active material layer includes an active material, graphene, and polyimide. The active material includes a plurality of nanowires each of which grows with a silicon particle used as a nucleus and extends in one direction into a fine needle. The graphene includes a region in contact with the plurality of nanowires, and polyimide includes a region in contact with the graphene. The lithium-ion secondary battery uses the electrode as a negative electrode.

Abstract: A power storage device with high capacity is provided. Alternatively, a power storage device with excellent cycle characteristics is provided. Alternatively, a power storage device with high charge and discharge efficiency is provided. Alternatively, a power storage device with a long lifetime is provided. A negative electrode active material includes a first region and a second region. The first region includes at least one element selected from Si, Mg, Ca, Ga, Al, Ge, Sn, Pb, Sb, Bi, Ag, Zn, Cd, As, Hg, and In. The second region includes oxygen and the same element as the one included in the first region. The crystallite size of the element included in the first region is larger than or equal to 1 nm and smaller than or equal to 10 nm.

Abstract: A highly reliable electrode for a lithium-ion secondary battery is provided. A highly reliable lithium-ion secondary battery is also provided using the electrode for a lithium-ion secondary battery. The electrode for a lithium-ion secondary battery includes a current collector and an active material layer. The active material layer includes an active material, graphene, and polyimide. The active material includes a plurality of nanowires each of which grows with a silicon particle used as a nucleus and extends in one direction into a fine needle. The graphene includes a region in contact with the plurality of nanowires, and polyimide includes a region in contact with the graphene. The lithium-ion secondary battery uses the electrode as a negative electrode.

Abstract: A power storage device with high capacity is provided. Alternatively, a power storage device with excellent cycle characteristics is provided. Alternatively, a power storage device with high charge and discharge efficiency is provided. Alternatively, a power storage device with a long lifetime is provided. A negative electrode active material includes a first region and a second region. The first region includes at least one element selected from Si, Mg, Ca, Ga, Al, Ge, Sn, Pb, Sb, Bi, Ag, Zn, Cd, As, Hg, and In. The second region includes oxygen and the same element as the one included in the first region. The crystallite size of the element included in the first region is larger than or equal to 1 nm and smaller than or equal to 10 nm.

Abstract: An electrode and a power storage device each of which achieves better charge-discharge cycle characteristics and is less likely to deteriorate owing to separation of an active material, or the like are manufactured. As the electrode for the power storage device, an electrode including a current collector and an active material layer that is over the current collector and includes a particle containing niobium oxide and a granular active material is used, whereby the charge-discharge cycle characteristics of the power storage device can be improved. Moreover, contact between the granular active material and the particle containing niobium oxide makes the granular active material physically fixed; accordingly, deterioration due to expansion and contraction of the active material which occur along with charge and discharge of the power storage device, such as powdering of the active material layer or its separation from the current collector, can be suppressed.

Abstract: A power storage device having high capacitance is provided. A power storage device with excellent cycle characteristics is provided. A power storage device with high charge and discharge efficiency is provided. A power storage device including a negative electrode with low resistance is provided. A negative electrode for the power storage device includes a current collector and an active material layer including a plurality of active material particles over the current collector. The active material particle is silicon, and the size of the silicon particle is greater than or equal to 0.001 ?m and less than or equal to 7 ?m.

Abstract: A novel element is provided. A novel film formation method is provided. A novel element manufacturing method is provided. Furthermore, a film including graphene is formed at low coat and high yield. The element includes a first electrode and a second electrode located apart from the first electrode. The first electrode and the second electrode include graphene. The film including graphene is formed through a first step of forming a film including graphene oxide over a substrate, a second step of immersing the film including graphene oxide in an acidic solution, and a third step of reducing graphene oxide included in the film including graphene oxide. Furthermore, before graphene oxide included in the film including graphene oxide is reduced, the film including graphene oxide is selectively removed by a photolithography technique.

Abstract: A power storage device with high capacity is provided. Alternatively, a power storage device with excellent cycle characteristics is provided. Alternatively, a power storage device with high charge and discharge efficiency is provided. Alternatively, a power storage device with a long lifetime is provided. A negative electrode active material includes a first region and a second region. The first region includes at least one element selected from Si, Mg, Ca, Ga, Al, Ge, Sn, Pb, Sb, Bi, Ag, Zn, Cd, As, Hg, and In. The second region includes oxygen and the same element as the one included in the first region. The crystallite size of the element included in the first region is larger than or equal to 1 nm and smaller than or equal to 10 nm.

Abstract: A power storage device which has improved performance such as higher discharge capacity and in which deterioration due to peeling or the like of an active material layer is less likely to be caused is provided. In an electrode for the power storage device, phosphorus-doped amorphous silicon is used for the active material layer over a current collector as a material that can be alloyed with lithium, and niobium oxide is deposited over the active material layer as a layer containing niobium. Accordingly, the capacity of the power storage device can be increased and the cycle characteristics and the charge-discharge efficiency can be improved.

Abstract: A power storage device having high capacitance is provided. A power storage device with excellent cycle characteristics is provided. A power storage device with high charge and discharge efficiency is provided. A power storage device including a negative electrode with low resistance is provided. A negative electrode for the power storage device includes a current collector and an active material layer including a plurality of active material particles over the current collector. The active material particle is silicon, and the size of the silicon particle is greater than or equal to 0.001 ?m and less than or equal to 7 ?m.

Abstract: A highly reliable electrode for a lithium-ion secondary battery is provided. A highly reliable lithium-ion secondary battery is also provided using the electrode for a lithium-ion secondary battery. The electrode for a lithium-ion secondary battery includes a current collector and an active material layer. The active material layer includes an active material, graphene, and polyimide. The active material includes a plurality of nanowires each of which grows with a silicon particle used as a nucleus and extends in one direction into a fine needle. The graphene includes a region in contact with the plurality of nanowires, and polyimide includes a region in contact with the graphene. The lithium-ion secondary battery uses the electrode as a negative electrode.

Abstract: A highly reliable semiconductor device is provided. The semiconductor device includes a first barrier insulating film; a first gate electrode thereover; a first gate insulating film thereover; an oxide semiconductor film thereover; source and drain electrodes over the oxide semiconductor film; a second gate insulating film over the oxide semiconductor film; a second gate electrode over the second gate insulating film; a second barrier insulating film that covers the oxide semiconductor film, the source and the drain electrodes, and the second gate electrode, and is in contact with side surfaces of the oxide semiconductor film and the source and drain electrodes; and a third barrier insulating film thereover. The first to third barrier insulating films are less likely to transmit hydrogen, water, and oxygen than the first and second gate insulating films. The third barrier insulating film is thinner than the second barrier insulating film.

Abstract: A power storage device with high capacity is provided. Alternatively, a power storage device with excellent cycle characteristics is provided. Alternatively, a power storage device with high charge and discharge efficiency is provided. Alternatively, a power storage device with a long lifetime is provided. A negative electrode active material includes a first region and a second region. The first region includes at least one element selected from Si, Mg, Ca, Ga, Al, Ge, Sn, Pb, Sb, Bi, Ag, Zn, Cd, As, Hg, and In. The second region includes oxygen and the same element as the one included in the first region. The crystallite size of the element included in the first region is larger than or equal to 1 nm and smaller than or equal to 10 nm.

Abstract: A novel element is provided. A novel film formation method is provided. A novel element manufacturing method is provided. Furthermore, a film including graphene is formed at low coat and high yield. The element includes a first electrode and a second electrode located apart from the first electrode. The first electrode and the second electrode include graphene. The film including graphene is formed through a first step of forming a film including graphene oxide over a substrate, a second step of immersing the film including graphene oxide in an acidic solution, and a third step of reducing graphene oxide included in the film including graphene oxide. Furthermore, before graphene oxide included in the film including graphene oxide is reduced, the film including graphene oxide is selectively removed by a photolithography technique.