Controllable and facile fabrication of gold nanostructures for selective metal-assisted etching of silicon

A method with the combination of organic-vapor-assisted polymer swelling and nanotransfer printing (nTP) is used to manufacture desirable patterns consisting of gold nano-clusters on silicon wafers for Au-assisted etching of silicon. This method remarkably benefits to the size control and regional selection of the deposited Au. By tuning the thickness of the Au films deposited on the polydimethylsiloxane (PDMS) stamps, along with the swelling of PDMS stamps in acetone atmosphere, the Au films are cracked into diverse nanostructures. These nanostructures are covalently transferred onto silicon substrates in a large scale and enable to accelerate the chemical etching of silicon. The etched areas are composed of porous structures which can be readily distinguished from the surroundings on optical microscope. PDMS stamps and the Au clusters provide the control over the feature of the etched areas and the porous silicon, respectively. The silicon surfaces with patterned porous features offer a platform for exploiting new functional templates, for example, they present a diversity of antireflective and fluorescent performance.