Structure, surface morphology and optical properties of post-annealed delafossite CuFeO2 thin films

Ab initio Study of Anchoring Groups for CuGaO2 Delafossite-Based p-Type Dye Sensitized Solar Cells

“…For simplicity, we have built an orthorhombic supercell with a ortho = a hexa , b ortho = √3 b hexa , and c ortho = c hexa (Figure 1B). For surface calculations, we considered the (011) surface (012 in the hexagonal system), which has been identified among the preferred facets of delafossite crystals (Das et al, 2015; Alkhayatt et al, 2016) and, in particular, has the lowest surface energy in CuGaO 2 (Schiavo et al, 2018). We cleaved such surface from orthorhombic bulk CuGaO 2 with the theoretically determined equilibrium lattice constants (a = b = 2.98 Å, c = 17.64 Å), which deviate <3% from the experimental values (a = b = 2.97 Å, c = 17.17Å) (Ishiguro et al, 1981; Köhler and Jansen, 1986; Crottaz et al, 1996) For electronic structure calculations, the (011) surface was represented as slab with a (2 × 1) periodicity in the xy plane, five tri-atom layers of thickness and 10.5 Å of vacuum, in order to avoid images interaction along the z direction (Figure 1C).…”

Influence of substrate temperature on delafossite CuFeO2 films synthesized by reactive magnetron sputtering

“…Different processes have been used to produce delafossite CuFeO2-based thin films, e.g. pulsed laser deposition [7] [15], spray pyrolysis [16] [17], sol-gel [18] [19] or radio-frequency sputtering [20][21] [22][23] [24]. It can be noted that an elevated substrate temperature or additional annealing step in neutral atmosphere or in primary vacuum is often required to obtain a crystalline structure, meaning that its synthesis without impurity phase is possible only for a limited range of oxygen partial pressures.…”

Band gap determination in multi-band-gap CuFeO2 delafossite epitaxial thin film by photoconductivity

“…The band gap results for CuFeO 2 have displayed strong absorption edges determined in the near infrared region ~ 1.2 eV [16][17][18][19][20][21]; absorption in the mid-visible region ~ 2.0 eV [22][23][24][25][26]; and absorption in higher energy, from blue to ultraviolet region ~ 3.0 eV [27][28][29][30][31][32][33][34]. Several groups have also reported multi-band gap results [22,23,25,26].…”