Fluorescent substance, method for producing the same, and light-emitting device using the same

-14. (canceled)

A method for producing a fluorescent substance comprising an α-sialon crystal having the same crystal structure with an α-type silicon nitride crystal, which includes at least an M(0) element (where M(0) represents one or two elements selected from Sr and La), an M(1) element (where M(1) represents one or more elements selected from Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb), Si, Al, and nitrogen, wherein

• one or more raw materials selected from MSiN2, M2Si5N8, M3Al2N4, and MSi6N8 are at least used as a starting material, in the form of an M-containing compound (where M represents one or more elements selected from divalent elements in the element group consisting of Sr and M(1)).

(canceled)

-28. (canceled)

(canceled)

A method for producing a fluorescent substance, wherein the method comprises:

• suspending a fluorescent substance comprising an α-sialon crystal structure having the same crystal structure with an α-type silicon nitride crystal, which includes at least an M(0) element (where M(0) represents one or two elements selected from Sr and La), an M(1) element (where M(1) represents one or more elements selected from Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb), Si, Al, and nitrogen, in an organic solvent;
• and adding an organometallic complex or metalalkoxide dropwise thereto, to thereby form a transparent layer in a thickness of (10 to 180)/n (unit:
• nanometer) on at least a part of the surfaces of a-sialon particles, provided that n represents a refractive index of the transparent layer within the range of 1.2 to 2.5.

A method for producing a fluorescent substance, wherein the method comprises;

• suspending a fluorescent substance comprising an α-sialon crystal structure having the same crystal structure with an α-type silicon nitride crystal, which includes at least an M(0) element (where M(0) represents one or two elements selected from Sr and La), an M(1) element (where M(1) represents one or more elements selected from Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb), Si, Al, and nitrogen, in water;
• and adding a metal salt aqueous solution dropwise thereto while keeping a constant pH, to thereby form a transparent layer in a thickness of (10 to 180)/n (unit:
• nanometer) on at least a part of the surfaces of a-sialon particles, provided that n represents a refractive index of the transparent layer within the range of 1.2 to 2.5.

-37. (canceled)