Raman spectra of P-, Sb-, or Bi-dopedGexSe1−

Effect of Bi doping on the structure and conduction mechanism of amorphous GeSe films

“…The viability of the models was assessed through comparison of the calculation results with experimental data. For the bismuth containing films, the ARDF model interpretation results corre late best with experimental data under the assumption that the Bi atoms are in threefold coordination, form ing pyramidal BiSe 3/2 groups linked to each other or through host chalcogen atoms; that is, Bi doping mod ifies the structure of the amorphous films so that the amorphous host contains, along with the host struc tural units a GeSе (tetrahedral coordination), atomic clusters similar in composition and coordination to quasi crystalline Bi 2 Sе 3 complexes, in agreement with earlier data [14]. V VI 2 3 А В Such structural changes account for the p to n type conversion in the (GeSe) 1 -x Bi x films in the composition range 0.11 < х < 0.15.…”

Annealing effects on the structure and optical properties of GeSe2 and GeSe4 films prepared by PLD

“…These differences can be attributed to more Se in the GeSe 4 film than that of the GeSe 2 film. Lastly, the shift of the peak positions near 175, 213 and 257 cm −1 toward the lower wavenumber compared with the corresponding GeSe 2 films can be ascribed to the weaker surrounding bonding environment [27]. The changes in as-deposited GeSe 4 film caused by annealing are similar with that in GeSe 2 film.…”

“…The weak shoulder near 175 cm −1 can be attributed to the vibrating of Se 3 Ge-GeSe 3 units. The main band near 197 cm −1 should be assigned to the A 1 vibration modes of the corner-sharing GeSe 4/2 tetrahedra [27]. The companion peak near 213 cm −1 can probably be assigned to the A c1 breathing vibrations of edge-shared Ge 2 Se 8/2 bi-tetrahedra [25,27].…”

Ab initio calculation of vibrational frequencies of GexSe1−x glass

“…Sugai [19] has pointed out that there is a threshold power at which crystallization into two structures occurs. Ikari et al [20] have studied the Raman spectra of Ge x Se 1Àx as a function of doping. It is suggested that 198 cm À1 is the breathing vibrational mode of methane like Ge(Se 1/2 ) 4 with A 1 symmetry whereas 216 cm À1 is due to Se tetrahedral units.The A 1 mode in corner sharing and in the edge sharing tetrahedrons have been discussed [21].…”