Local structural change of amorphous Ge–Sb–Te thin film on annealing

Smallest (∼10nm) phase-change marks in amorphous and crystalline Ge2Sb2Te5 films

“…This radius is consistent with the size (~10 nm) of minimal crystalline marks. It should be mentioned that this scale is also comparable to reported sizes of crystalline grains produced optically [23] and thermally [24], which may lend supports to this rough idea. However, a simple extension of this model to the c→a change, ∆G c→a = ∆G a + ∆G ac , cannot be accepted.…”

Microstructural evolution and metastable phase formation in laser ablation-deposited films of Fe-rich Fe–Ge intermetallic compounds

“…It has been conclusively established that the reason for clustering in these alloys is the presence of inflection points (@ 2 G=@x 2 j T¼Tc ¼ 0, where G is free energy and x denotes composition) in the free energy curve of the liquid/amorphous phase at lower temperatures. This has been suggested as the reason for the tendency of phase separation [27] in these alloys. The free energy expression of liquid phase of Fe-Ge alloys has been estimated by Kanibolorsky et al [28] using calorimetric measurements in the temperature range 1250-1580 K. These authors have pointed out that a strong interaction exists between atoms of different types in the Fe-Ge alloy metals.…”

“…It also corroborates the findings of Chopra et al [25], who reported the existence of metal clusters in the amorphous films of Fe-Ge alloys with concentration 410 at% Ge. Several reports of nano-scale clustering in multi-component bulk amorphous alloys are available in the literature [26,27]. It has been conclusively established that the reason for clustering in these alloys is the presence of inflection points (@ 2 G=@x 2 j T¼Tc ¼ 0, where G is free energy and x denotes composition) in the free energy curve of the liquid/amorphous phase at lower temperatures.…”

“…Experimental and computational Figure 8. Free energy versus composition plot of amorphous phase, calculated according to [27].…”

Generation of phase-change Ge–Sb–Te nanoparticles by pulsed laser ablation

“…Recently, phase-change optical/electrical memory utilizes fast and reversible phase-changes simultaneously with the differences in optical reflectance and in electrical resistivity between the amorphous and the crystalline phase states of some chalcogenide materials [2,3]. To achieve higher densities than what are presently accessible from commercial phase-change optical memory products or prototypes of non-volatile phase-change electrical memory, certain major technical problems have to be overcome, which involves modification, integration, and development of materials for targeting superior functions.…”