Insight into the role of nitrogen in the phase-change material Sb

Abstract

The influence of nitrogen dopant on the structure of the phase-change material Sb has been investigated by ab initio molecular dynamics simulations. The doped N exist as SbN complex in amorphous phase and would not enter into the rhombohedra phase of crystalline Sb. During crystallization of the amorphous phase, no N 2 molecule is formed and part of the N-Sb bonds are broken to release Sb atoms which contribute to growth of crystal nuclei by forming more Sb-Sb bonds. Remaining N-Sb bonds would segregate at the grain boundaries and retard growth of crystal nuclei.

High‐pressure and high‐temperature synthesis of crystalline Sb3N5

“…According to ab initio molecular dynamics simulations, the local formation of four-coordinated NSb 4 tetrahedra sharing corners or edges seems to drive the bonding mechanism of N to Sb in amorphous N-doped Sb, persisting also after crystallization and apparently representing an important feature in phase change materials performances of N-doped amorphous Sb. [12,13] Within this scenario, the existence and evolution with pressure of the trigonal prismatic hexa-coordination into a square antiprismatic octa-coordination, including the two additional distances in the coordination sphere, represents a unique feature among crystalline pnictogen nitrides.…”

“…Beyond the pure advancement of fundamental chemical knowledge about the chemistry of Sb and N, understanding the stability of the SbÀ N system in terms of structure, composition and metastability, is technologically relevant for the synthesis of phase change memory and thermoelectric materials [12][13][14] and of semiconductors for applications in optoelectronics, photovoltaics and photoelectrochemical cells. [15,16] Moreover, further interest concerns the intriguing properties predicted by calculations for the different 2D polymorphs of single layer SbÀ N materials such as α-, [17] β- [18] and δ-SbN.…”

Mechanism of Corrosion Selectivity of NSb2Te Thin Films in the H3PO4/HNO3 Developer for Direct Laser Writing Nanolithography

“…For the exposed thin film, however, part of the N–Sb bonds are broken to release Sb atoms, forming more Sb–Sb bonds with lower corrosion potential and charge transfer resistance. Remaining N–Sb bonds would segregate at the grain boundaries and retard the growth of Sb crystal nuclei . In parallel, the exposed NST thin film generates amounts of Te grains with lone-pair electrons, which are uniformly dispersed in the thin film.…”

“…Remaining N−Sb bonds would segregate at the grain boundaries and retard the growth of Sb crystal nuclei. 43 In parallel, the exposed NST thin film generates amounts of Te grains with lone-pair electrons, which are uniformly dispersed in the thin film. Thus, the exposed NST thin film has nucleophilicity due to the lonepair electrons of the Te atom, which may readily provide electrons in a chemical reaction.…”

High‐pressure and high‐temperature synthesis of crystalline Sb3N5

“…According to ab initio molecular dynamics simulations, the local formation of four-coordinated NSb 4 tetrahedra sharing corners or edges seems to drive the bonding mechanism of N to Sb in amorphous N-doped Sb, persisting Angewandte Chemie also after crystallization and apparently representing an important feature in phase change materials performances of N-doped amorphous Sb. [12,13] Within this scenario, the existence and evolution with pressure of the trigonal prismatic hexa-coordination into a square antiprismatic octa-coordination, including the two additional distances in the coordination sphere, represents a unique feature among crystalline pnictogen nitrides.…”