MOCVD growth of Ga2Se3 on GaAs(100) and GaP(100): a Raman study

Allotropic Ga2Se3/GaSe nanostructures grown by van der Waals epitaxy: narrow exciton lines and single-photon emission

“…The measured band gap values of mono - and ortho -Ga 2 Se 3 are characterized by a large scatter and depend both on the methods of film preparation and on the spectroscopic techniques. 28,30–33 However, the difference in band gap between these phases is always within 0.5 eV and the mono phase has a higher energy, which is in good agreement with theoretical calculations. 27,34…”

“…29 The measured band gap values of mono-and ortho-Ga 2 Se 3 are characterized by a large scatter and depend both on the methods of film preparation and on the spectroscopic techniques. 28,[30][31][32][33] However, the difference in band gap between these phases is always within 0.5 eV and the mono phase has a higher energy, which is in good agreement with theoretical calculations. 27,34 Despite the unique properties of bulk Ga 2 Se 3 , the Ga 2 Se 3 / GaSe nanostructures, which may be similar to quantum dots (QDs), have not yet been created and studied.…”

“…It was suggested that the latter may be due to short-range interactions in the Ga 2 Se 3 unit cell. 57 Thus, the observed combination of modes in the Raman spectrum point to coexistence of ε -GaSe and vacancy-ordered Ga 2 Se 3 .…”

Peculiarities of Ga and Te incorporation in glassy arsenic selenides

“…5, Table 4) of the investigated samples suggests the value for the average local coordination number around Ga close to 4 when there is no Te in the composition, like in the case of other Gamodified selenide glasses [20,21] or Ga 2 Se 3 crystal [37]. However, the increase in Te content leads to a detectable increase in Ga coordination beyond four (simultaneous changes in Debye-Waller factor are not so significant), which is a somewhat unexpected result ( (Table 4), which can be attributed to the preferable tetrahedral coordination of Ga in crystalline compounds with chalcogens [38]. On the other hand, the Ga 3d core level electron XPS spectra can be well fitted with only one doublet with main component (3d 5/2 ) at ~19.3 eV for all Te-containing glassy samples ( Fig.…”

Devitrification of Bi- and Ga-containing germanium-based chalcogenide glasses

“…The third family of low-intensity peaks within ~180-210 cm -1 range, most probably, originate from GeSe 4 tetrahedra, where one or two Se atoms are replaced with Te. The Raman peaks of Ga-based complexes, expected at ~105, ~118, ~155, ~250, ~290 cm -1 (for Ga 2 Se 3 [34,35]) and ~117, ~130 cm -1 (breathing modes of GaTe 4/2 units [36]), are hardly observed in Raman spectra of the investigated glasses because of the low Ga concentration (5 at.%) and their strong overlap with other modes of telluride-based units. The crystalline Bi 2 Se 3 usually gives rise to Raman bands at ~75, ~130 and ~175 cm -1 [37][38][39], while Bi 2 Te 3 Raman active modes lie at ~62, ~104, ~134 cm -1 [40,41].…”