Solution deposition of chalcogenide films

A second method of depositing a film of a metal chalcogenide, comprising the steps of:

• contacting:
• at least one metal chalcogenide and a salt of an amine compound with H2S, H2Se or H2Te, wherein said amine compound is represented by the formula:
• NR5R6R7
• wherein each of R5, R6 and R7 is independently selected from the group consisting of:
• hydrogen, aryl, methyl, ethyl and a linear, branched or cyclic alkyl of 3-6 carbon atoms, to produce an ammonium-based precursor of said metal chalcogenide;
• contacting said ammonium-based precursor of said metal chalcogenide, a hydrazine compound represented by the formula:
• R1R2N—NR3R4
• wherein each of R1, R2, R3 and R4 is independently selected from the group consisting of:
• hydrogen, aryl, methyl, ethyl and a linear, branched or cyclic alkyl of 3-6 carbon atoms, and optionally, an elemental chalcogen selected from the group consisting of:
• S, Se, Te and a combination thereof;
• to produce a solution of a hydrazinium-based precursor of said metal chalcogenide in said hydrazine compound;
• applying said solution of said hydrazinium-based precursor of said metal chalcogenide onto a substrate to produce a film of said precursor;
• and thereafter
• annealing said film of said precursor to remove excess hydrazine and hydrazinium chalcogenide salts to produce a metal chalcogenide film on said substrate.

A method of preparing an improved field-effect transistor of the type having a source region and a drain region, a channel layer extending between the source region and the drain region, the channel layer including a semiconducting material, a gate region disposed in spaced adjacency to the channel layer, an electrically insulating layer between the gate region and the source region, drain region and channel layer, wherein the improvement comprises:

• preparing a channel layer comprising a film of a metal chalcogenide semiconducting material by a first or second method;
• wherein said first method comprises the steps of:
• contacting:
• at least one metal chalcogenide;
• a hydrazine compound represented by the formula:
• R1R2N—NR3R4
• wherein each of R1, R2, R3 and R4 is independently selected from the group consisting of:
• hydrogen, aryl, methyl, ethyl and a linear, branched or cyclic alkyl of 3-6 carbon atoms;
• and optionally, an elemental chalcogen selected from the group consisting of:
• S, Se, Te and a combination thereof;
• to produce a solution of a hydrazinium-based precursor of said metal chalcogenide;
• applying said solution of said hydrazinium-based precursor of said metal chalcogenide onto a substrate to produce a film of said precursor;
• and thereafter
• annealing said film of said precursor to remove excess hydrazine and hydrazinium chalcogenide salts to produce a metal chalcogenide film;
• and
• wherein said second method comprises the steps of:
• contacting:
• at least one metal chalcogenide and a salt of an amine compound with H2S, H2Se or H2Te, wherein said amine compound is represented by the formula:
• NR5R6R7
• wherein each of R5, R6 and R7 is independently selected from the group consisting of:
• hydrogen, aryl, methyl, ethyl and a linear, branched or cyclic alkyl of 3-6 carbon atoms, to produce an ammonium-based precursor of said metal chalcogenide;
• contacting said ammonium-based precursor of said metal chalcogenide, a hydrazine compound represented by the formula:
• R1R2N—NR3R4
• wherein each of R1, R2, R3 and R4 is independently selected from the group consisting of:
• hydrogen, aryl, methyl, ethyl and a linear, branched or cyclic alkyl of 3-6 carbon atoms, and optionally, an elemental chalcogen selected from the group consisting of:
• S, Se, Te and a combination thereof, to produce a solution of a hydrazinium-based precursor of said metal chalcogenide in said hydrazine compound;
• applying said solution of said hydrazinium-based precursor of said metal chalcogenide onto a substrate to produce a film of said precursor;
• and thereafter
• annealing said film of said precursor to remove excess hydrazine and hydrazinium chalcogenide salts to produce a metal chalcogenide film on said substrate.

A method of preparing a metal chalcogenide film in a field-effect transistor, comprising steps of:

• contacting at least one metal chalcogenide and (i) a hydrazine compound or (ii) first an ammonium salt compound and thereafter a hydrazine compound to produce a solution of a hydrazinium-based precursor of said metal chalcogenide;
• applying said solution of said hydrazinium-based precursor of said metal chalcogenide onto a substrate to produce a film of said precursor;
• and
• annealing said film of said precursor under conditions sufficient to produce said metal chalcogenide film.