Electroconductive tin oxide having high mobility and low electron concentration

1. A method for preparing a doped, p-type tin oxide layer on a substrate, the method comprising the step of:

depositing the tin oxide layer on the substrate by atmospheric pressure chemical vapor deposition using a tin oxide precursor in a carrier gas; in which:

the tin oxide precursor comprises a vaporizable tin compound;

the tin oxide precursor comprises less than about 0.01 weight percent total d and f transition metals;

the carrier gas comprises nitrogen, nitrous oxide, and oxygen;

the flow rates are nitrogen, 2-20 L/min; nitrous oxide, 1-10 L/min; and oxygen, 20-160 cm 3 /min; and

the carrier gas additionally comprises a dopant precursor;

the dopant precursor is an Al, Ga, or In compound; and

the resulting tin oxide is doped, p-type tin oxide.

2. The method of claim 1 in which the tin oxide layer has a hole concentration of at least about 1×10 17 cm −3 .

3. The method of claim 1 in which the tin oxide layer has a hole concentration of 0.3-100×10 16 cm −3 at room temperature.

4. The method of claim in which the dopant is Al.

5. The method of claim 3 in which the dopant is Ga.

6. The method of claim 2 in which the dopant is In.

7. The method of claim 1 in which the dopant precursor is (R 1 ) n M(R 2 ) m , in which R 1 is a C 1 -C 8 straight, branched, aliphatic, cycloaliphatic or unsaturated hydrocarbyl, R 2 is a bidentate ligand that bonds through oxygen atoms; M is Al, Ga, or In; m is 1 or 2; n is 1 or 2; and n+m=3.

8. The method of claim 7 in which R 1 is methyl or ethyl, and R 2 is acac, tmhd, or hfac.

9. The method of claim 7 in which the tin oxide layer has a hole concentration of at least about 1×10 17 cm −3 .

10. The method of claim 9 in which the flow rates are nitrogen, 4-10 L/min; nitrous oxide, 2-4 L/min; and oxygen, 50-100 cm 3 /min.