Structure Evolution in Chemical Vapor-Deposited ZnS Films

Abstract

The evolution of the crystallographic structure of ZnS films (thickness ≈ 2 μm) grown on Si(100) wafers by the single-source chemical vapor deposition (CVD) of zinc dimethyldithiocarbamate precursor has been examined. X-ray and electron diffraction indicated that the films were cubic (sphalerite) and oriented preferentially along the (111) direction. Transmission electron microscopy (TEM) indicated that the films were composed of a uniformly distributed array of columns approximately 300−500 nm wide. High-resolution TEM at the interface showed that these columns were attached to the substrate surface via smaller columns (∼50−100 nm wide). The density of crystallographic defects in the bulk columns was lower than that in the interfacial columns. Orientation of the crystallites occurred at a much earlier stage in film growth compared to theoretical predictions for evaporative deposited films, suggesting that the presence of impurities during chemical vapor deposition may influence the structural evolution of the film.

Combinatorial Discovery and Optimization of Amorphous HfO[sub 2]–Nb[sub 2]O[sub 5] Mixture with Improved Transparency

“…It is the case here because the presence of the columns is an indication of the island growth. 29 Therefore SZM suggests that the film, whose side-view SEM is depicted in Fig. 2c, is composed of columns that are separated with small voids that were not visible in the SEM.…”

“…28 SZM was developed to explain the micro-and nanostructure of the films produced by physical vapor deposition methods, but it has also shown to be useful for films deposited by CVD. 29 According to this model the growth of amorphous films begins with small columns ͑ϳ1 to 3 nm͒ up to ϳ15 nm thickness. As the film grows, four other characteristic column sizes, 5-20, 20-40, 50-200, and 200-400 nm ͑ϳ10 m thickness͒, appear.…”

ZnS nanostructures: From synthesis to applications

“…ZnS thin films have been fabricated by several techniques, such as vacuum deposition [283], successive ionic layer adsorption and reaction process (SILAR) [284][285][286], metal-organic chemical vapor deposition (MOCVD) [287,288], molecular beam epitaxy (MBE) [289,290], spray pyrolysis [291,292], chemical bath deposition (CBD) [293,294], pulse-laser deposition [295,296], atomic layer epitaxy (ALE) [297,298], sputtering [299], sol-gel [300,301], and chemical vapor deposition [302,303]. For example, Herrero and co-workers synthesized ZnS films by CBD with a decent growth rate using NH 2 -NH 2 as a complementary complexing agent for the classically used NH 3 reaction baths.…”

The Effect of the Deposition Method on the Structural and Optical Properties of ZnS Thin Films

“…ZnS thin films have been successfully obtained by a wide variety of deposition techniques such as thermal evaporation [17], molecular beam epitaxy [18,19], sol gel deposition [20], chemical bath deposition [21], pulse laser deposition [22,23], magnetron sputtering [24], or chemical vapor deposition [25].…”