A microstructural and compositional analysis of CuInSe2 ingots grown by the vertical Bridgman technique

Lattice dynamics and related properties of AIBIII and AIIBIV compounds, I. Elastic constants

“…Fouret et al [70] do not give any details of the growth conditions or the structural properties of their sample, except that the crystal was fabricated using the horizontal Bridgman technique. It is well known that this method leads to unavoidable compositional inhomogeneities in the material [73][74][75] caused by specific features of the phase diagram of the Cu-In-Se system along the Cu 2 Se-In 2 Se 3 quasibinary cut [76]. The elemental composition of crystals grown from stoichiometric melts varies from slightly indium rich at the first-to-freeze end to slightly indium deficient at the last-to-freeze end.…”

“…The elemental composition of crystals grown from stoichiometric melts varies from slightly indium rich at the first-to-freeze end to slightly indium deficient at the last-to-freeze end. The capability of the material to accommodate rather large deviations from stoichiometry and still to crystallise in the chalcopyrite structure finds its explanation in the formation of high concentrations of point defects (vacancies, antisite defects, interstitials) [77,78] and point defect complexes [13], extended structural defects (dislocations, stacking faults, twins) [78,79], orientation domains [80][81][82] separated by small angle grain boundaries [83], and microscopic inclusions of secondary phases in the chalcopyrite matrix [75,81,84]. As an additional complication it must be taken into account that, firstly, there are orientation domains with the CuAu-ordered structure [82] with lattice vibrational characteristics differing from those of the chalcopyrite lattice [85,86] and, secondly, the bond configurations at grain boundaries can considerably differ from the bonding properties in the bulk chalcopyrite matrix [87].…”

The CuGaSe2–CuInSe2–2CdS system and single crystal growth of the γ-phase

“…Therefore, measurements of the band gap were done for the middle of the ingots, where the composition is assumed to be the closest to the nominal [23,28].…”

“…It was not possible to unambiguously determine conductivity type for all crystals by the ''hot probe'' method, presumably because of the existence of the compositional gradient along the crystal growth direction [23,28].…”

Study on the properties of CuInSe2 ingots grown from the melt using stoichiometric and non-stoichiometric charges

“…Furthermore, it has also been found that the physical properties of bulk CIS were strongly dependent on compositional deviations from the ideal stoichiometry and the precipitation of secondary phases. The uniformity of the crystal properties was generally tributary of the growth process, including the fabrication technique, starting materials composition, temperature patterns, and crucible nature [10][11][12][13][14].…”