Near infrared optical and photoelectric properties of Cu2O II. Near infrared Photoconductivity in Cu2O: Influence of annealing

Abstract

The near infrared photoresponse spectra of three classes of Cu2O samples have been investigated at 295, 110 and 10 K. At 295 K the spectra of the first class samples annealed in very high vacuum show two thresholds at 1.9 and ≈︁ 1.4 eV. Those of the second class of samples analogous to those investigated by Prevot et al. (Part I) show two more thresholds at 1.65 and ≈︁ 0.9 eV. For the samples of the third class expected to have a high oxygen excess, two thresholds at 1.9 and 1.65 eV and a diffuse one located near 0.55 eV, have been observed. At low and very low temperatures, more structures have been observed on samples of the second and third classes. In addition to one photoresponse minimum at 1.9 eV that shifts with temperature, two more minima at 0.97 eV and 0.76 eV corresponding to absorption maxima have been found. Further weaker structures have been observed at 1.19, 1.11, 1.05, and ≈︁ 0.9 eV. In Part III of this work the interpretation of the experimental results will be presented in connection with the absorption data of Part I.

Evaluation of defects in cuprous oxide through exciton luminescence imaging

“…Two phonon transitions are also known in silicon [40] and graphene [41]. An additional extrinsic feature has been reported at about 1.91 eV in other work [42,43,20,44,45].…”

Probing Defects in Nitrogen-Doped Cu2O

“…The as-grown Cu 2 O:N sample exhibited a unique signature located at ~652 nm (1.90 eV). This signal did not originate from the β band in nonstoichiometric Cu 2 O, despite the very similar energy level (1.91 eV) because the β band created by exciton-defect complexes would not be affected by the annealing process2728. It cannot be related to N O ; if it were, it would not have disappeared after annealing.…”

Formation of shallow boron emitters in crystalline silicon using flash lamp annealing: Role of excess silicon interstitials

“…Cu 2 O has a rich defect fauna and acceptor and donor levels have been reported at 0.08-1.08 eV above E v [85][86][87][88][89][90][91][92][93][94][95][96]. There seems to exist a general consesus that the Cu vacancy (v Cu ) is the dominant acceptor giving rise to the intrinsic p-type conduction in Cu 2 O [97][98][99][100], but experimentally the exact position of the defect level is disputed [88-90, 92, 101], although most reports place its level around 0.25 eV above E v .…”