Method of providing a wrinkle pattern or producing a substrate having a wrinkle pattern of a single layer
Disclosed herein is a method of producing a substrate having a wrinkle pattern of a single-layer rhenium disulfide (ReS 2 ) nanoflakes deposited thereon. The method is characterized by using ammonium rhenium and sulfur powders as the rhenium source and the sulfur source, respectively; and with the addition of molecular sieve to control the release of the rhenium source during the deposition of ReS 2 , in which a single layer of ReS 2 is deposited on a substrate via chemical vapor deposition. The single-layer ReS 2 is then exposed to UV light to induce the formation of a wrinkle pattern.
1. A method of producing a substrate having a wrinkle pattern of a single-layer rhenium disulfide (ReS 2 ) nanoflakes deposited thereon in a reaction chamber, in which the reaction chamber has a tubular body having first and second temperature zones, and first and second containers, the method comprises,
(a) placing sulfur powders in the first container;
(b) placing ammonium perrhenate evenly in the second container;
(c) covering the evenly placed ammonium perrhenate of step (b) with a plurality of molecular sieves;
(d) mounting the substrate above the plurality of molecular sieves of step (c);
(e) placing the first container of step (a) and the second container of step (d) into the tube furnace, in which the first and second containers are respectively under the first and second temperature zones;
(f) purging the reaction chamber of the step (e) with an inert gas, in which the inert gas flows from the first temperature zone towards the second temperature zone;
(g) subjecting the reaction chamber in a heating program, in which the temperature in the first temperature zone is raised from room temperature to 200° C. in 30 minutes and kept for 10 minutes, while the temperature in the second temperature zone is raised from room temperature to 600-950° C. in 30 minutes and kept for 10 minutes;
(h) allowing the temperature of the second temperature zone to cool down to 600° C.;
(i) cooling the reaction chamber to room temperature thereby depositing the single-layer ReS 2 nanoflakes on the substrate; and
(j) irradiating the substrate of step (i) with ultraviolet (UV) light until the single-layer ReS 2 nanoflakes deposited thereon forms the wrinkle pattern.
2. The method of claim 1 , wherein the sulfur powders and the ammonium perrhenate are present in a ratio of 10:1 by weight.
3. The method of claim 2 , wherein the sulfur powders and the ammonium perrhenate are present in the ratio of 7:1 by weight.
4. The method of claim 1 , wherein the substrate is a mica substrate or a sapphire substrate.
5. The method of claim 1 , wherein the inert gas is nitrogen or argon.
6. The method of claim 5 , wherein in the step (f), the reaction chamber is purged with argon at a flow rate of 50-100 cm 3 /min.
7. The method of claim 6 , wherein the reaction chamber is purged with argon at the flow rate of 80 cm 3 /min.
8. The method of claim 1 , wherein in the step (j), the irradiation is performed in a humidity level of 30-80% in the presence of the inert gas for a period of 60-450 seconds.
9. The method of claim 8 , wherein the irradiation is performed with two UV lights respectively set at the wavelengths of 254 nm and 185 nm.
10. The method of claim 9 , wherein the inert gas is nitrogen.