Micropatterned Arrays of ZnSe Nanospheres as Antireflection Coatings

Abstract

In this work, we demonstrate deposition of micro-arrays of ZnSe nanospheres on Si (100) substrate using simple thermal evaporation on a self-assembled sacrificial polystyrene (PS) mask. The results have been compared with the deposition on unpatterned gold catalyst- and SU-8 (negative photoresist)-coated Si substrates. The deposited ZnSe nanospheres properties were characterised by X-ray diffraction, atomic force microscopy (AFM), scanning electron microscopy (SEM), Raman, photoluminescence, and UV-vis spectroscopies. The X-ray diffraction patterns of the films exhibited reflection corresponding to the cubic (111) phase and showed polycrystallinity with a cubic (zinc blende) structure. The SEM and AFM images indicated that the particles were well dispersed and spherical in shape. The micro-arrays of ZnSe nanospheres on a self-assembled sacrificial PS mask showed excellent structural, morphological, and optical properties and demonstrated its usage in photovoltaic devices as an improved superior antireflective coating. The reflectance of the micro-arrays of ZnSe nanospheres on a self-assembled sacrificial PS mask decreased to nearly half of that of the ZnSe nanospheres fabricated on Au- and SU-8-coated Si substrates in the range of 300–800 nm. Due to the well aligned and patterned surfaces, these noble textured ZnSe nanospheres may be suitable for low cost, large area photovoltaic devices and other antireflection applications.