Electronic structure of the hole-doped delafossite oxides CuCr1−xMgxO2

X-ray spectroscopic studies of the electronic structure of chromium-basedp-type transparent conducting oxides

“…For in situ cleaved samples, the increase in photoemission intensity at resonance was 0.003, in line with the observed intensity changes in the copper deficient Cu x CrO y films investigated here [28].…”

“…3, the structure in the Cu L-edge around 926 eV is found to be more intense in the better conducting Cu 0.4 Cr 1 O 2.5 sample even after sputtering. A similar structure was found to appear in Mg doped CuCrO 2 , increasing in intensity with magnesium concentration by Yokobori et al [28]. The appearance of the same structure in copper deficient material suggests that the origin of the peak is a copper atom in a different electronic configuration in some defect complex involving the copper site and, e.g., an adjacent oxygen interstitial (O i ).…”

“…The prepeak at hν ≈ 926 eV, which has been reported as an XAS final state of 2p3d 10 , which corresponds to an initial 3d 9 state, i.e., Cu 2+ impurities, is observed in the as-grown films and re-emerges with oxygen annealing [37]. The same prepeak, but significantly reduced in argon sputtered samples, is observed for Mg doped CuCrO 2 and stoichiometric CuCrO 2 [26,28]. In our Cu x CrO y films, it decreases with, but is not eliminated by argon sputtering and re-appears with oxygen annealing.…”

“…The first reports from theoretical and experimental studies suggested that Cu states lay at the top of the valence band [24][25][26]. Further DFT+U studies by Scanlon and Watson, and experimental confirmation by Yokobori et al using resonant valence-band photoemission spectroscopy (RVBPES) showed evidence that in fact chromium states predominately compose the top of the valence band [27,28].…”

Transparent conductive CuCrO2thin films deposited by pulsed injection metal organic chemical vapor deposition: up-scalable process technology for an improved transparency/conductivity trade-off

“…Copper chromium oxides contrast with other delafossites, in terms of: (i) high density of state of 3d M cations (Cr 3+ ) near the valence band maximum, (ii) covalent mixing between chromium and oxygen ions and (iii) good dopability, [17][18][19][20][21][22] making CuCrO 2 a good p-type candidate for transparent electronic devices. Several methods were reported in the literature for the synthesis of CuCrO 2 : solid-state reaction (SS), 17,[20][21][22][23][24][25][26][27][28][29][30] sol-gel (SG), [31][32][33][34][35][36][37] pulsed laser deposition (PLD), [38][39][40][41][42] magnetron sputtering (MS) 16,[43][44][45][46] and chemical vapor deposition (CVD) including spray pyrolysis. [47][48][49][50] A summary of the electrical and optical properties versus the synthesis methods and the process temperature is given in are obtained with the films deposited by sol-gel, due to the low carrier concentration.…”