To produce hexagonal boron nitride (h-BN), boron and nitrogen are added to a metallic solvent in a crucible in a reaction chamber and heat-treated. In an absorption step, a first soak is performed at a first temperature that is high enough to cause absorption of the nitrogen and boron into the metallic solvent. In a nucleation step after the absorption step, the first temperature is rapidly reduced to a second temperature, and h-BN nuclei are formed in the metallic solvent. In a growth step after the nucleation step, a second soak is performed at the second temperature to grow the h-BN nuclei. After the growth step, the h-BN nuclei are separated from the metallic solvent.

To produce hexagonal boron nitride (h-BN), boron and nitrogen are added to a metallic solvent in a crucible in a reaction chamber and heat-treated. In an absorption step, a first soak is performed at a first temperature that is high enough to cause absorption of the nitrogen and boron into the metallic solvent. In a nucleation step after the absorption step, the first temperature is rapidly reduced to a second temperature, and h-BN nuclei are formed in the metallic solvent. In a growth step after the nucleation step, a second soak is performed at the second temperature to grow the h-BN nuclei. After the growth step, the h-BN nuclei are separated from the metallic solvent.

Proposed are a layered compound having indium and arsenic, a nanosheet that may be prepared using the same, and an electrical device including the materials. Proposed is a layered compound represented by [Formula 1] Na.sub.1-xIn.sub.yAs.sub.z (0≤x<1.0, 0.8≤y≤1.2, 1.2≤z≤1.8).

Proposed are a layered compound having indium and phosphide, a nanosheet that may be prepared using the same, and an electrical device including the materials. Proposed is a layered compound represented by K.sub.1-xIn.sub.yP.sub.z (0≤x≤1.0, 0.75≤y≤1.25, 1.25≤z≤1.75).

The disclosure relates to a semimetal compound of Pt and a method for making the same. The semimetal compound is a single crystal material of PtSe.sub.2. The method comprises: providing a PtSe.sub.2 polycrystalline material; placing the PtSe.sub.2 polycrystalline material in a reacting chamber; placing chemical transport medium in the reacting chamber; evacuating the reacting chamber to be vacuum less than 10 Pa; placing the reacting chamber at a temperature gradient, wherein the reacting chamber has a first end at a temperature of 1200 degrees Celsius to 1000 degrees Celsius and a second end opposite to the first end and at a temperature of 1000 degrees Celsius to 900 degrees Celsius; and keeping the reacting chamber in the temperature gradient for 10 days to 30 days.

The disclosure relates to a semimetal compound of Pt and a method for making the same. The semimetal compound is a single crystal material of PtSe.sub.2. The method comprises: providing a PtSe.sub.2 polycrystalline material; placing the PtSe.sub.2 polycrystalline material in a reacting chamber; placing chemical transport medium in the reacting chamber; evacuating the reacting chamber to be vacuum less than 10 Pa; placing the reacting chamber at a temperature gradient, wherein the reacting chamber has a first end at a temperature of 1200 degrees Celsius to 1000 degrees Celsius and a second end opposite to the first end and at a temperature of 1000 degrees Celsius to 900 degrees Celsius; and keeping the reacting chamber in the temperature gradient for 10 days to 30 days.

The disclosure relates to a method for making semimetal compound of Pt. The semimetal compound is a single crystal material of PtSe.sub.2. The method comprises: placing pure Pt and pure Se in a reacting chamber as reacting materials; evacuating the reacting chamber to be vacuum less than 10 Pa; heating the reacting chamber to a first temperature of 600 degrees Celsius to 800 degrees Celsius and keeping for 24 hours to 100 hours; cooling the reacting chamber to a second temperature of 400 degrees Celsius to 500 degrees Celsius at a cooling rate of 1 degrees Celsius per hour to 10 degrees Celsius per hour and keeping for 24 hours to 100 hours to obtain a crystal material of PtSe.sub.2; and separating the excessive reacting materials from the crystal material of PtSe.sub.2.

The disclosure relates to a method for making semimetal compound of Pt. The semimetal compound is a single crystal material of PtSe.sub.2. The method comprises: placing pure Pt and pure Se in a reacting chamber as reacting materials; evacuating the reacting chamber to be vacuum less than 10 Pa; heating the reacting chamber to a first temperature of 600 degrees Celsius to 800 degrees Celsius and keeping for 24 hours to 100 hours; cooling the reacting chamber to a second temperature of 400 degrees Celsius to 500 degrees Celsius at a cooling rate of 1 degrees Celsius per hour to 10 degrees Celsius per hour and keeping for 24 hours to 100 hours to obtain a crystal material of PtSe.sub.2; and separating the excessive reacting materials from the crystal material of PtSe.sub.2.

A method for a SiC single crystal that allow prolonged growth to be achieved are provided. A method for producing a SiC single crystal in which a seed crystal substrate held on a seed crystal holding shaft is contacted with a Si—C solution having a temperature gradient such that a temperature of the Si—C solution decreases from an interior of the Si—C solution toward a liquid level of the Si—C solution, in a graphite crucible, to grow a SiC single crystal, wherein the method comprises the steps of: electromagnetic stirring of the Si—C solution with an induction coil to produce a flow, and heating of a lower part of the graphite crucible with a resistance heater.

A method for a SiC single crystal that allow prolonged growth to be achieved are provided. A method for producing a SiC single crystal in which a seed crystal substrate held on a seed crystal holding shaft is contacted with a Si—C solution having a temperature gradient such that a temperature of the Si—C solution decreases from an interior of the Si—C solution toward a liquid level of the Si—C solution, in a graphite crucible, to grow a SiC single crystal, wherein the method comprises the steps of: electromagnetic stirring of the Si—C solution with an induction coil to produce a flow, and heating of a lower part of the graphite crucible with a resistance heater.