A method of manufacturing a lead salt thin film on a substrate by seeding a substrate with a lead salt solution (e.g., PbSe, PbS, or PbTe) to form a seeded substrate comprising lead salt seed crystals, and growing the lead salt thin film upon the substrate by exposing the seeded substrate to a chemical bath comprising the lead salt solution at a predetermined growth temperature. A lead salt thin film manufactured by the process. A photonic crystal microchip comprising the lead salt thin film. A gas sensing device comprising a diode laser, a mid-infrared photodetector, and the photonic crystal microchip. A method of detecting a hydrocarbon gas, comprising exposing a gas sample to the gas sensing device, and determining the content of hydrocarbon gases in the gas sample.

A solar cell of an embodiment includes a p-electrode, an n-electrode, a p-type light-absorbing layer located between the p-electrode and the n-electrode and mainly containing a cuprous oxide, and an n-type layer that includes a first n-type layer which is located between the p-type light-absorbing layer and the n-electrode, which mainly contains a compound represented by Ga.sub.v1Zn.sub.v2Sn.sub.v3M1.sub.v4O.sub.v5, the M1 being one or more selected from the group consisting of Hf, Zr, In, Ti, Al, B, Mg, Si, and Ge, the v1, the v2, and the v4 being numerical values of 0.00 or more, the v3 and the v5 being numerical values of more than 0, at least one of the v1 and the v2 being a numerical value of more than 0, and the v5 when a sum of the v1, the v2, the v3, and the v4 is 1 being 1.00 or more and 2.00 or less, and which is located on the n-electrode side, and a second n-type layer which is a layer that mainly contains a compound represented by Ga.sub.w1M2.sub.w2M3.sub.w3M4.sub.w4O.sub.w5, the M2 being Al or/and B, the M3 is one or more selected from the group consisting of In, Ti, Zn, Hf, and Zr, the M4 being one or more selected from the group consisting of Sn, Si, and Ge, the w1 and the w5 being numerical values of more than 0, the w2, the w3, and the w4 being numerical values of 0.00 or more, and the w5 when a sum of the w1, the w2, the w3, and the w4 is 2 being 3.00 or more and 3.80 or less, and which is located on the p-type light-absorbing layer side.

Provided is a Mg.sub.2Si single crystal in which generation of low-angle grain boundaries in the crystal is satisfactorily suppressed. A Mg.sub.2Si single crystal, wherein a variation in crystal orientation as measured by XRD is in a range of ±0.020°.

Provided is a Mg.sub.2Si single crystal in which generation of low-angle grain boundaries in the crystal is satisfactorily suppressed. A Mg.sub.2Si single crystal, wherein a variation in crystal orientation as measured by XRD is in a range of ±0.020°.

A radiation detector includes a halide semiconductor sandwiched a cathode and an anode and a buffer layer between the halide semiconductor and the anode. The anode comprises a composition selected from: (a) an electrically conducting inorganic-oxide composition, (b) an electrically conducting organic composition, and (c) an organic-inorganic hybrid composition. The buffer layer comprises a composition selected from: (a) a composition distinct from the composition of the anode and including at least one other electrically conducting inorganic-oxide composition, electrically conducting organic composition, or organic-inorganic hybrid composition; (b) a semi-insulating layer selected from: (i) a polymer-based composition; (ii) a perovskite-based composition; (iii) an oxide-semiconductor composition; (iv) a polycrystalline halide semiconductor; (v) a carbide, nitride, phosphide, or sulfide semiconductor; and (vi) a group II-VI or III-V semiconductor; and (c) a component metal of the halide-semiconductor.

A radiation detector includes a halide semiconductor sandwiched a cathode and an anode and a buffer layer between the halide semiconductor and the anode. The anode comprises a composition selected from: (a) an electrically conducting inorganic-oxide composition, (b) an electrically conducting organic composition, and (c) an organic-inorganic hybrid composition. The buffer layer comprises a composition selected from: (a) a composition distinct from the composition of the anode and including at least one other electrically conducting inorganic-oxide composition, electrically conducting organic composition, or organic-inorganic hybrid composition; (b) a semi-insulating layer selected from: (i) a polymer-based composition; (ii) a perovskite-based composition; (iii) an oxide-semiconductor composition; (iv) a polycrystalline halide semiconductor; (v) a carbide, nitride, phosphide, or sulfide semiconductor; and (vi) a group II-VI or III-V semiconductor; and (c) a component metal of the halide-semiconductor.

The present disclosure relates to a method of patterning a thin-film photovoltaic layer stack (20), the method comprising the steps of:—providing of a continuous layer stack (20), the layer stack (20) comprising a planar substrate (21), a first electrode layer (22) on the substrate (21) and a photovoltaic layer (24) on the electrode layer (22),—immersing the layer stack (20) into an electrically conductive solution (40),—applying a bias voltage between the electrolyte solution (40) and the first electrode layer (22) and—converting of a first material (51, 53) or a first material composition provided in at least a first portion (50, 52, 54) of the layer stack (20) into a first reaction product (56) by an electrochemical reaction, wherein the first reaction product (56) has an electrical conductivity that is lower than an electrical conductivity of the first material (51, 53) or first material composition, or—removing a first material (51, 53) or a first material composition provided in at least a first portion (50, 52, 54) of the layer stack (20) by an electrochemical reaction.

Structures and methods for manufacturing photovoltaic devices by forming perovskite layers and perovskite precursor layers using vapor transport deposition (VTD) are described.

A method for controlling a concentration of donors in an Al-alloyed gallium oxide crystal structure includes implanting a Group IV element as a donor impurity into the crystal structure with an ion implantation process and annealing the implanted crystal structure to activate the Group IV element to form an electrically conductive region. The method may further include depositing one or more electrically conductive materials on at least a portion of the implanted crystal structure to form an ohmic contact. Examples of semiconductor devices are also disclosed and include a layer of an Al-alloyed gallium oxide crystal structure, at least one region including the crystal structure implanted with a Group IV element as a donor impurity with an ion implantation process and annealed to activate the Group IV element, an ohmic contact including one or more electrically conductive materials deposited on the at least one region.

Disclosed are a hybrid structure using a graphene-carbon nanotube and a perovskite solar cell using the same. The hybrid structure includes a graphene-carbon nanotube formed by laminating a second graphene coated with a polymer on an upper surface of a first graphene coated with a carbon nanotube. The perovskite solar cell includes: a substrate; a first electrode formed on the substrate and including a fluorine doped thin oxide (FTO); an electron transfer layer formed on the first electrode and including a compact-titanium oxide (c-TiO.sub.2); a mesoporous-titanium oxide (m-TiO.sub.2) formed on the electron transfer layer; a perovskite layer formed on the m-TiO.sub.2 and including a perovskite compound; and a graphene-carbon nanotube hybrid structure formed on the perovskite layer.