CPC C23C 18/145 (2019.05) [C09D 11/52 (2013.01); C23C 18/1671 (2013.01); C23C 18/1682 (2013.01); C23C 18/31 (2013.01); B22F 1/18 (2022.01)] | 30 Claims |
1. A method for forming a crystalline metal layer on a three-dimensional (3D) substrate, comprising:
applying crystal growth ink to a surface of the 3D substrate, wherein the crystal growth ink includes a metal ionic precursor and a mixture of a spreading liquid having a surface tension between 10 and 40 millinewton per meter (mN/m) and a structuring liquid having a dynamic viscosity between 10-1000 centipoise (cP) and a vapor pressure between 0-100 pascals (Pa); and
exposing the crystal growth ink to low temperature radio frequency (RF) plasma irradiation in a vacuum environment to cause the growing of a crystalline metal layer on the 3D substrate, wherein the exposure is based on a set of predefined exposure parameters; wherein the metal ionic precursor is HAuCl4 with a concentration ranging from 5 wt. % and 20 wt. %;
wherein the structuring liquid comprises at least one of Dipropylene glycol methyl ether with a concentration of 16 wt. % and Ethylene glycol with a concentration of 41 wt. %;
wherein the spreading liquid comprises Propanol with a concentration of 32 wt. %; and
wherein the set of predefined exposure parameters includes RF frequency of 13.56 MHz, 150 W of power, 25 SCCM gas flow rate, and the pressure within a chamber is 0.6 mbar; resulting in a continuous layer of gold nanoparticles ranging from 20 to 100 nm in size.
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