Breath Figure-Assisted Fabrication of Nanostructured Coating on Silicon Surface and Evaluation of Its Antireflection Power

Abstract

We report our recent results on the fabrication of nanostructured polymer layers aimed at developing efficient antireflection coating on silicon. The proposed manufacturing approach is based on self-assembly and relies on breath figure formation. By simple and straightforward operations, we are able to produce different nanostructured coatings: densely packed nanodomes, randomly distributed nanopores, and multilayered close-packed nanopores. By optical reflectivity measurements on coated silicon wafers, we show that the latter type of nanostructure is able to reduce the reflectivity of standard silicon surface (≈40% at 450 nm) to about 10%.

Breath-Figure Self-Assembly, a Versatile Method of Manufacturing Membranes and Porous Structures: Physical, Chemical and Technological Aspects

“…Various experimental techniques were successfully applied for breath-figure self-assembly, including drop-casting [ 66 , 67 , 68 , 69 , 70 , 71 ], spin-coating [ 72 , 73 , 74 , 75 , 76 , 77 , 78 ], the “doctor-blade” technique [ 79 , 80 ], and dip-coating [ 46 , 54 , 58 , 81 , 82 , 83 ]. When breath-figures-inspired patterns are formed under drop-casting, a drop of polymer solution is deposited by a precise micro-syringe (or micro-injector) on a solid substrate and exposed to air flow with a controlled humidity [ 66 , 67 , 68 , 69 , 70 , 71 ].…”

“…The substrate is then rotated at high speed in order to spread the evaporated polymer solution by centrifugal force. The whole process is performed under controlled humidity [ 72 , 73 , 74 , 75 , 76 , 77 , 78 ]. In the doctor-blade technique, an immobilized blade applies a unidirectional shear force to the polymer solution that passes through a small gap between the blade and the substrate [ 79 , 80 , 81 ].…”

Nano- and Micropatterning on Optical Fibers by Bottom-Up Approach: The Importance of Being Ordered

“…The potentiality of this technology is extensive, especially in terms of production speed: fabricating a colloidal 2DPC takes tenths of minutes to hours; making a pattern by breath figures takes a few seconds to 2-3 min. Thanks to its extreme simplicity and fast realization, the breath figure process has been applied in materials science in a great number of studies and for different applications [64][65][66][67][68][69][70][71]. For nanofabrication purposes, breath figure arrays can also represent the starting structure from which different kinds of patterns can be developed by further fabrication steps such as electrodeposition [72], pyrolysis [73], or dry etching [74].…”

Breath-Figures Self-Assembly, the Versatile Method of Manufacturing Membranes and Porous Structures: Physical, Chemical and Technological Aspects

“…Various experimental techniques were successfully applied for the breath figures self-assembly, including: drop-casting [66][67][68][69][70][71], spin-coating [72][73][74][75][76][77][78], the "doctor-blade" technique [79][80] and dip-coating [46,54,58,[81][82][83]. When breath-figures inspired patterns are formed under drop-casting a drop of polymer solution is deposited by the precise micro-syringe (or micro-injector) on the solid substrate and exposed to the air flow possessing controlled humidity [66][67][68][69][70][71].…”

“…The substrate is then rotated at high speed in order to spread the evaporated polymer solution by centrifugal force. All the process is performed under controlled humidity [72][73][74][75][76][77][78]. In the doctor-blade technique an immobilized blade applies a unidirectional shear force to the polymer solution that passes through a small gap between the blade and the substrate [79][80]84].…”