A method for manufacturing a CZTS based thin film having a dual band gap slope, comprising the steps of: forming a Cu.sub.2ZnSnS.sub.4 thin film layer; forming a Cu.sub.2ZnSn(S,Se).sub.4 thin film layer; and forming a Cu.sub.2ZnSnS.sub.4 thin film layer. A method for manufacturing a CZTS based solar cell having a dual band gap slope according to another aspect of the present invention comprises the steps of: forming a back contact; and forming a CZTS based thin film layer on the back contact by the method described above.

A direct solution method based on a versatile amine-thiol solvent mixture which dissolves elemental metals, metal salts, organometallic complexes, metal chalcogenides, and metal oxides is described. The metal containing and metal chalcogenide precursors can be prepared by dissolving single or multiple metal sources, chalcogens, and/or metal chalcogenide compounds separately, simultaneously, or stepwise. Multinary metal chalcogenides containing at least one of copper, zinc, tin, indium, gallium, cadmium, germanium, and lead, with at least one of sulfur, selenium, or both are obtained from the above-mentioned metal chalcogenide precursors in the form of thin films, nanoparticles, inks, etc. Furthermore, infiltration of metal containing compounds into a porous structure can be achieved using the amine-thiol based precursors. In addition, due to the appreciable solubility of metal sources, metal chalcogenides, and metal oxides in the mixture of amine(s) and thiol(s), this solvent mixture can be used to remove these materials from a system.

A method is disclosed for making semiconductor films from a eutectic alloy comprising a metal and a semiconductor. Through heterogeneous nucleation said film is deposited at a deposition temperature on relatively inexpensive buffered substrates, such as glass. Specifically said film is vapor deposited at a fixed temperature in said deposition temperature where said deposition temperature is above a eutectic temperature of said eutectic alloy and below a temperature at which the substrate softens. Such films could have widespread application in photovoltaic and display technologies.

Transistor structures with monocrystalline metal chalcogenide channel materials are formed from a plurality of template regions patterned over a substrate. A crystal of metal chalcogenide may be preferentially grown from a template region and the metal chalcogenide crystals then patterned into the channel region of a transistor. The template regions may be formed by nanometer-dimensioned patterning of a metal precursor, a growth promoter, a growth inhibitor, or a defected region. A metal precursor may be a metal oxide suitable, which is chalcogenated when exposed to a chalcogen precursor at elevated temperature, for example in a chemical vapor deposition process.

A method of preparing a heterojunction material, includes forming a first transition metal on a substrate, forming a second transition metal on the first transition metal, and performing a plasma process containing a chalcogen source on the substrate. The first transition metal and the second transition metal are different from each other.

A method for forming a semiconductor device having a lateral semiconductor heterojunction involves forming a first metal chalcogenide layer of the lateral semiconductor heterojunction adjacent to a first metal electrode on a substrate. The first metal chalcogenide layer includes a same metal as the first metal electrode and at least some of the first metal chalcogenide layer includes metal from the first metal electrode. A second metal chalcogenide layer of the lateral semiconductor heterojunction is formed adjacent to the first metal chalcogenide layer. A second metal electrode is formed adjacent to the second metal chalcogenide layer. The second metal chalcogenide layer includes a same metal as the second metal electrode.

A method of performing HVPE heteroepitaxy comprises exposing a substrate to a carrier gas, a first precursor gas, a Group II/III element, and ternary-forming gasses (V/VI group precursor), to form a heteroepitaxial growth of a binary, ternary, and/or quaternary compound on the substrate; wherein the carrier gas is H.sub.2, wherein the first precursor gas is HCl, the Group II/III element comprises at least one of Zn, Cd, Hg, Al, Ga, and In; and wherein the ternary-forming gasses comprise at least two or more of AsH.sub.3 (arsine), PH.sub.3 (phosphine), H.sub.2Se (hydrogen selenide), H.sub.2Te (hydrogen telluride), SbH.sub.3 (hydrogen antimonide, or antimony tri-hydride, or stibine), H.sub.2S (hydrogen sulfide), NH.sub.3 (ammonia), and HF (hydrogen fluoride); flowing the carrier gas over the Group II/III element; exposing the substrate to the ternary-forming gasses in a predetermined ratio of first ternary-forming gas to second ternary-forming gas (1tf:2tf ratio); and changing the 1tf:2tf ratio over time.

Disclosed is a formulation of semiconductor nanoplatelets, including at least one nanoplatelet including a nanoplatelet core and a shell on the surface of the nanoplatelet core, wherein the formulation is substantially free of molecular oxygen and/or molecular water, and uses thereof.

A method of preparing a heterojunction material, includes forming a first transition metal on a substrate, forming a second transition metal on the first transition metal, and performing a plasma process containing a chalcogen source on the substrate. The first transition metal and the second transition metal are different from each other.

Atomic layer deposition (ALD) processes for forming Te-containing thin films, such as Sb—Te, Ge—Te, Ge—Sb—Te, Bi—Te, and Zn—Te thin films are provided. ALD processes are also provided for forming Se—containing thin films, such as Sb—Se, Ge—Se, Ge—Sb—Se, Bi—Se, and Zn—Se thin films are also provided. Te and Se precursors of the formula (Te,Se)(SiR.sup.1R.sup.2R.sup.3).sub.2 are preferably used, wherein R.sup.1, R.sup.2, and R.sup.3 are alkyl groups. Methods are also provided for synthesizing these Te and Se precursors. Methods are also provided for using the Te and Se thin films in phase change memory devices.