A solution deposition method including: applying a liquid precursor solution to a substrate, the precursor solution including an oxide of a first metal, a hydroxide of the first metal, or a combination thereof, dissolved in an aqueous ammonia solution; evaporating the precursor solution to directly form a solid seed layer on the substrate, the seed layer including an oxide of the first metal, a hydroxide of the first metal, or a combination thereof, the seed layer being substantially free of organic compounds; and growing a bulk layer on the substrate, using the seed layer as a growth site or a nucleation site.

A solution deposition method including: applying a liquid precursor solution to a substrate, the precursor solution including an oxide of a first metal, a hydroxide of the first metal, or a combination thereof, dissolved in an aqueous ammonia solution; evaporating the precursor solution to directly form a solid seed layer on the substrate, the seed layer including an oxide of the first metal, a hydroxide of the first metal, or a combination thereof, the seed layer being substantially free of organic compounds; and growing a bulk layer on the substrate, using the seed layer as a growth site or a nucleation site.

A method is provided for making smooth crystalline semiconductor thin-films and hole and electron transport films for solar cells and other electronic devices. Such semiconductor films have an average roughness of 3.4 nm thus allowing for effective deposition of additional semiconductor film layers such as perovskites for tandem solar cell structures which require extremely smooth surfaces for high quality device fabrication.

A method for making an epitaxial structure includes the following steps. A substrate having an epitaxial growth surface is provided. A carbon nanotube layer is placed on the epitaxial growth surface. A buffer layer is formed on the epitaxial growth surface. A first epitaxial layer is epitaxially grown on the buffer layer. The substrate and the buffer layer are separated to form a second epitaxial growth surface. A second epitaxial layer is epitaxially grown on the second epitaxial growth surface.

A method for making an epitaxial structure includes the following steps. A substrate having an epitaxial growth surface is provided. A buffer layer is formed on the epitaxial growth surface. A carbon nanotube layer is placed on the buffer layer. A first epitaxial layer is epitaxially grown on the buffer layer. The substrate and the buffer layer are removed to expose a second epitaxial growth surface. A second epitaxial layer is epitaxially grown on the second epitaxial growth surface.

A method for making an epitaxial structure includes the following steps. A substrate having an epitaxial growth surface is provided. A buffer layer is formed on the epitaxial growth surface. A carbon nanotube layer is placed on the buffer layer. A first epitaxial layer is epitaxially grown on the buffer layer. The substrate and the buffer layer are removed to expose a second epitaxial growth surface. A second epitaxial layer is epitaxially grown on the second epitaxial growth surface.

A method for making an epitaxial structure includes the following steps. A substrate having an epitaxial growth surface is provided. A buffer layer is formed on the epitaxial growth surface. A carbon nanotube layer is placed on the buffer layer. A first epitaxial layer is epitaxially grown on the buffer layer. The substrate and the buffer layer are removed to expose a second epitaxial growth surface. A second epitaxial layer is epitaxially grown on the second epitaxial growth surface.

A method for making an epitaxial structure includes the following steps. A substrate having an epitaxial growth surface is provided. A buffer layer is formed on the epitaxial growth surface. A carbon nanotube layer is placed on the buffer layer. A first epitaxial layer is epitaxially grown on the buffer layer. The substrate and the buffer layer are removed to expose a second epitaxial growth surface. A second epitaxial layer is epitaxially grown on the second epitaxial growth surface.

Disclosed are methods and mask structures for epitaxially growing substantially defect-free semiconductor material. In some embodiments, mask structure includes a first level defining a first trench extending through the first level, wherein a bottom of the first trench is defined by a semiconductor substrate, and a second level on top of the first level, wherein the second level defines a plurality of second trenches positioned at a non-zero angle with respect to the first trench.

Provided are an organic semiconductor film and a preparation method thereof. The preparation method includes at least the following steps: preparing an inorganic nanocrystal with a shell structure, performing synchronous ion exchange on an anion and a metal ion in the inorganic nanocrystal with the shell structure to obtain a modified inorganic nanocrystal with a shell structure and a relatively stable structure, dispersing the modified inorganic nanocrystal with the shell structure and a conjugated organic small molecule in an organic solvent to obtain a dispersion, and forming the dispersion into the organic semiconductor film.