NOVELTY - The apparatus comprises preformed inorganic nanocrystals, non-hydrocarbon, non-crystalline barrier materials, electrically conducting materials in electrical contact with the barrier material, and a substrate. The inorganic nanocrystals are in electrical contact with the barrier materials, and comprise a III-V semiconductor material. A potential energy barrier exists against transferring carriers between barrier material and inorganic nanocrystals. The inorganic nanocrystals are formed in a first layer on top of a second layer of a first non-hydrocarbon, non-crystalline barrier material.    USE - Used as an apparatus including optoelectronic device such as nanostructures-based photovoltaic solar cell and LED, and electronic device such as detector, modulator or emitter.    ADVANTAGE - The apparatus can be efficiently and economically manufactured with improved performance and high-throughput.    DETAILED DESCRIPTION - The apparatus comprises preformed inorganic nanocrystals, non-hydrocarbon, non-crystalline barrier materials, electrically conducting materials in electrical contact with the barrier material, and a substrate. The inorganic nanocrystals are in electrical contact with the barrier materials, and comprise a III-V semiconductor material. A potential energy barrier exists against transferring carriers between the barrier material and the inorganic nanocrystals. The inorganic nanocrystals are formed in a first layer on top of and in electrical contact with a second layer of a first non-hydrocarbon, non-crystalline barrier material, where the second layer is placed on top of and in electrical contact with a third layer of a first electrically conducting material. A fourth layer of a second non-hydrocarbon, non-crystalline barrier material is formed on top of and in electrical contact with the first layer of the inorganic nanocrystals. A fifth layer of a second electrically conducting material is formed on top of the fourth layer, and is in electrical contact with the fourth layer. The third and a fifth layer of electrically conducting material is transparent to frequencies of electromagnetic radiation, where the frequencies are in ultraviolet to infra-red region. A nanocrystal layer absorbs light centered on wavelengths. The frequencies of electromagnetic radiation pass through the transparent conducting material, and are absorbed in the inorganic nanocrystals to produce an electrical current flow between the third and fifth layers. A direction of the electrical current flow between the third and fifth layers are determined by a built-in potential formed by electrical contact regions of different work functions and different electron affinities of the materials of the second and fourth layers. The nanocrystal layer is a compound layer formed by layers of nanocrystals separated by barrier materials. A distribution of absorbed wavelengths is determined by size, shape and material of the nanocrystals. An additional layer of material is present between the pairs comprising the second and third layers and the fourth and fifth layers, and facilitates electrical contact between the layers. The barrier material comprises layers of different compositions, and nitride or oxide containing compounds. The carriers transported to the inorganic nanocrystals recombine and produce electromagnetic radiation. The layers of material is interposed between the barrier material and the nanocrystal, and facilitates electrical contact between the barrier material and the nanocrystal. The inorganic nanocrystal is derived from a colloidal solution of nanocrystals, and has a shape consisting of spherical, oval, rod, wire and plate. Energy states of the inorganic nanocrystal are determined in part by quantum confinement in dimensions. The electromagnetic radiation incident on the inorganic nanocrystals is absorbed to produce a light modulator. The carriers transported through the barrier material are transported by quantum tunneling, thermionic emission and diffusion. The nanocrystal is a semiconductor material crystal.    DESCRIPTION OF DRAWING(S) - The diagram shows a sectional view of an apparatus such as solar cell.    Optional electrically conducting layer (12)    Layer of barrier material (14)    Layer of preformed nanocrystals (20)    Contact layer (32)    Optional additional layers of material. (40, 42, 44, 46)