A RAMO.sub.4 substrate containing an RAMO.sub.4 base material part containing a single crystal represented by the general formula RAMO.sub.4 (wherein R represents one or a plurality of trivalent elements selected from a group of elements including: Sc, In, Y, and a lanthanoid element, A represents one or a plurality of trivalent elements selected from a group of elements including: Fe(III), Ga, and Al, and M represents one or a plurality of divalent elements selected from a group of elements including: Mg, Mn, Fe(II), Co, Cu, Zn, and Cd), the RAMO.sub.4 base material part having a beveled portion at an edge portion thereof.

A RAMO.sub.4 substrate containing an RAMO.sub.4 base material part containing a single crystal represented by the general formula RAMO.sub.4 (wherein R represents one or a plurality of trivalent elements selected from a group of elements including: Sc, In, Y, and a lanthanoid element, A represents one or a plurality of trivalent elements selected from a group of elements including: Fe(III), Ga, and Al, and M represents one or a plurality of divalent elements selected from a group of elements including: Mg, Mn, Fe(II), Co, Cu, Zn, and Cd), the RAMO.sub.4 base material part having a beveled portion at an edge portion thereof.

A RAMO.sub.4 substrate includes a single crystal represented by a formula of RAMO.sub.4 (in the formula, R indicates one or a plurality of trivalent elements selected from a group consisting of Sc, In, Y, and a lanthanoid element, A indicates one or a plurality of trivalent elements selected from a group consisting of Fe(III), Ga, and Al, and M indicates one or a plurality of bivalent elements selected from a group consisting of Mg, Mn, Fe(II), Co, Cu, Zn, and Cd). An epitaxially-grown surface is provided on at least one surface of the RAMO.sub.4 substrate. An unevenness having a height of 500 nm or more is not provided on the epitaxially-grown surface.

A RAMO.sub.4 substrate includes a single crystal represented by a formula of RAMO.sub.4 (in the formula, R indicates one or a plurality of trivalent elements selected from a group consisting of Sc, In, Y, and a lanthanoid element, A indicates one or a plurality of trivalent elements selected from a group consisting of Fe(III), Ga, and Al, and M indicates one or a plurality of bivalent elements selected from a group consisting of Mg, Mn, Fe(II), Co, Cu, Zn, and Cd). An epitaxially-grown surface is provided on at least one surface of the RAMO.sub.4 substrate. An unevenness having a height of 500 nm or more is not provided on the epitaxially-grown surface.

A RAMO.sub.4 substrate is formed from single crystal represented by a formula of RAMO.sub.4 (in the formula, R indicates one or a plurality of trivalent elements selected from a group consisting of Sc, In, Y, and a lanthanoid element, A indicates one or a plurality of trivalent elements selected from a group consisting of Fe(III), Ga, and Al, and M indicates one or a plurality of bivalent elements selected form a group consisting of Hg, Mn, Fe(II), Co, Cu, Zn, and Cd). An epitaxially-grown surface is provided on at least one surface of the RAMO.sub.4 substrate. The epitaxially-grown surface includes a plurality of cleavage surfaces which are regularly distributed, and are separated from each other.

A RAMO.sub.4 substrate is formed from single crystal represented by a formula of RAMO.sub.4 (in the formula, R indicates one or a plurality of trivalent elements selected from a group consisting of Sc, In, Y, and a lanthanoid element, A indicates one or a plurality of trivalent elements selected from a group consisting of Fe(III), Ga, and Al, and M indicates one or a plurality of bivalent elements selected form a group consisting of Hg, Mn, Fe(II), Co, Cu, Zn, and Cd). An epitaxially-grown surface is provided on at least one surface of the RAMO.sub.4 substrate. The epitaxially-grown surface includes a plurality of cleavage surfaces which are regularly distributed, and are separated from each other.

A RAMO.sub.4 substrate includes a single crystal represented by a formula of RAMO.sub.4 (in the formula, R indicates one or a plurality of trivalent elements selected from a group consisting of Sc, In, Y, and a lanthanoid element, A indicates one or a plurality of trivalent elements selected from a group consisting of Fe(III), Ga, and Al, and M indicates one or a plurality of bivalent elements selected from a group consisting of Mg, Mn, Fe(II), Co, Cu, Zn, and Cd). An epitaxially-grown surface is provided on one surface of the RAMO.sub.4 substrate, a satin-finish surface is provided on another surface. The satin-finish surface has surface roughness which is larger than that of the epitaxially-grown surface.

A RAMO.sub.4 substrate includes a single crystal represented by a formula of RAMO.sub.4 (in the formula, R indicates one or a plurality of trivalent elements selected from a group consisting of Sc, In, Y, and a lanthanoid element, A indicates one or a plurality of trivalent elements selected from a group consisting of Fe(III), Ga, and Al, and M indicates one or a plurality of bivalent elements selected from a group consisting of Mg, Mn, Fe(II), Co, Cu, Zn, and Cd). An epitaxially-grown surface is provided on one surface of the RAMO.sub.4 substrate, a satin-finish surface is provided on another surface. The satin-finish surface has surface roughness which is larger than that of the epitaxially-grown surface.

The present disclosure discloses a method for growing a crystal with a short decay time. According to the method, a new single crystal furnace and a temperature field device are adapted and a process, a ration of reactants, and growth parameters are adjusted and/or optimized, accordingly, a crystal with a short decay time, a high luminous intensity, and a high luminous efficiency can be grown without a co-doping operation.

The present disclosure discloses a method for growing a crystal with a short decay time. According to the method, a new single crystal furnace and a temperature field device are adapted and a process, a ration of reactants, and growth parameters are adjusted and/or optimized, accordingly, a crystal with a short decay time, a high luminous intensity, and a high luminous efficiency can be grown without a co-doping operation.