Influence of Hydrogenation on the Amorphous-to-Crystalline Phase Transition Characteristics of Ge₂Sb₂Te₅ and Ge₈Sb₂Te₁₁ Thin Films

Abstract

The characteristics of amorphous-to-crystalline phase transformation in the hydrogenated Ge 2 Sb 2 Te 5 and Ge 8 Sb 2 Te 11 thin films were investigated by X-ray diffraction (XRD), optical transmittance (T OP ), and nano-pulse reflection response. The hydrogenation was conducted under a H 2 pressure (P H ) of 20 atm and an annealing temperature (T a ) of 100 and 200 C. The incorporation of hydrogens into the chalcogenide films was verified by secondary ion mass spectrometry (SIMS) depth profile. The variation of H-signals in the SIMS profile was apparently compensated by the variation of Sb and Ge signals rather than by that of Te. The results measured in hydrogenated films were compared with those in the as-deposited and post-annealed films at T a for 4 h in pure N 2 atmosphere. The hydrogenation effects led to very different dependences between the Ge 2 Sb 2 Te 5 and Ge 8 Sb 2 Te 11 thin films. Amorphous-to-crystalline phase-transition speed was evaluated via nano-pulse reflection response measurement. The hydrogenation inhibited the transition of Ge 2 Sb 2 Te 5 but hardly affected that of Ge 8 Sb 2 Te 11 . In particular, the amorphous-to-crystalline transition in the hydrogenated Ge 8 Sb 2 Te 11 film was very stable.

Structure and Dynamics of Ionic Liquids Confined in Amorphous Porous Chalcogenides

“…Using a realistic model of GeS 2 surface developed by means of first-principles calculations, we investigate the effect of surface chemistry by considering both bare and hydrogenated GeS 2 surfaces. Such a study is motivated by the fact that hydrogenation is expected to affect the properties of chalcogenide surfaces. , To determine the density of the IL confined in chalcogels in conditions similar to those encountered in experiments, we perform MD in the isobaric–isothermal ensemble (NPT). While a realistic all-atom strategy was used to produce these models, they are not necessarily representative of experimental samples obtained by synthesizing nanoporous chalcogenides or chalcogenide nanoparticles in ionic liquids.…”

Nanoscale Phase Separation and Building Blocks of Ge2Sb2Te5N and Ge2Sb2Te5N2 Thin Films

“…The aim, to improve its characteristics for technological applications and also to understand the factors leading to the observed behavior, has sparked an interest into its substituted or doped variants. Previously, properties of several differently doped or substituted GST materials have been investigated both experimentally and theoretically. − In this paper we focus on nitrogen doped GST.…”

Universal memory based on phase-change materials: From phase-change random access memory to optoelectronic hybrid storage*

“…V [130] Zr [133] Se [132] …… InP [131] C [125] N [107] O [108] Si [110] B [115] Sn [117] In [119] Ag [112] Al [123] Zn [116] Cr [114] O(N) [109] S [111] Pd [113] Fe [116] Bi(B) [118] H [120] Ga [121] Mo [122] Ti [124] Ce [126] Mn [127] Mg [128] Bi [129] BN [134] O [192] Si [184][185][186] In [170,171] Ag [172,173] Al [174][175][176][177] Cr [193,194] Ge [166][167][168] Au [169] (Y,Sc ) [201] TiO 2 [198] SiN ...…”

“…[144] Carbon atoms are found to significantly enhance the thermal stability of amorphous GST by increasing the degree of disorder of the amorphous phase based on simulations [145] and experiments [146,147] because the carbon dopant forms a germanium carbide phase and atomic scale carbon clusters. [120] The FCC phase stability of the GST-C film was maintained by carbon doping after annealing at 440 • C and the grain size of the GST-C film was significantly decreased due to the presence of carbon in the form of clusters or precipitating at the grain boundaries. [148] The microscopic C-doping role was unraveled based on ab initio calculations.…”