Stability of metastable GeTe2 in thin films

Anomalous Raman modes in tellurides

“…The most striking point is that most of the bands observed in the ARS of GaTe and GaGeTe, especially the two strongest ones, have been observed in a number of 2D and bulk Te-based chalcogenides with different laser wavelenghts (typically with green and red lasers), irrespective of their different compositions and crystalline structures. They have been observed in ZnTe, 7,8 CdTe, [9][10][11][12][13][14] GaTe, [15][16][17][18][19][20][21][22] As2Te3, 23 Sb2Te3, 24,25 Bi2Te3, 26,27 GeTe, 28,29 SnTe and PbTe, 30,31 GeTe2, [32][33][34][35] TiTe2, [36][37][38][39] GaGeTe, 6 SnSb2Te4, 40 and crystalline Ge2Sb2Te5, 41 to name a few. A search among different tellurides shows that in most cases the first and more intense ARM is observed between 119 and 130 cm -1 , while the second ARM is usually observed between 139 and 145 cm -1 .…”

Scrutiny of structural disorder using Raman spectra and Tauc parameter in GeTe2 thin films

“…Germanium and tellurium with 4 and 2 valences, respectively, easily saturate the bond requirement upon rearrangement. This structural rearrangement can be explained by chemical bond energy process [9] that says: (i) The formation of heteropolar bonds favor more likely than the homopolar bonds (ii) depending on the valance requirement the atoms prefer to bond among each other and (iii) the higher bonding energy is preferable. In GeTe2 system, Ge-Ge, Te-Te and Ge-Te bonds are formed depending on the structural changes taking place at the host network.…”

“…In GeTe2 system, Ge-Ge, Te-Te and Ge-Te bonds are formed depending on the structural changes taking place at the host network. The bond energies of homopolar and heteropolar bonds are as follows: Ge-Ge (157.3 KJ/mol), Te-Te (138.1 KJ/mol) and Ge-Te (157.3 KJ/mol) [9]. Stronger bonds of Ge-Ge and Ge-Te are formed initially and later the weaker bonds of TeTe are formed in excess as of chalcogenides.…”

IR laser-induced synthesis of nanostructured gemanium telluride in the gas phase

“…The latter undergoes disproportionation GeTe 2 → GeTe + Ge, and its stability increases with increasing film thickness. 35 All these species might be formed during the laser pulse. We assume that the reaction between the tellurium and germanium clusters takes place inside the hot laser zone (characterized by the temperature gradients 25 ) at different temperatures within several microseconds.…”