Photoelectric properties of cuprous oxide

Abstract

The effects of transient and steady-state illumination on the electrical properties of single-crystal cuprous oxide have been investigated in the temperature range from 230 to -20°C. For samples equilibrated well within the region of Cu,O stability, conduction was governed by an acceptor level at 0.4 eV above the valence band as determined from the temperature dependence of the Hall effect. The presence of two minority carrier trapping levels was also established and trapping parameters were determined from an analysis of the transient photoconductivity. The 0.4-eV acceptor level was also found to be present in a sample equilibrated under conditions placing its composition in a region near the CuO-Cu,O phase boundary. For this sample, however, only a single deeper trapping level was observed. A third type of sample, equilibrated under conditions which placed its composition in a region near the Cu-Cu,O phase boundary, was characterized by both a high hole density and a high mobility with an acceptor level energy of 0.16 eV. Also, the presence of two effects, the thermal quenching of the steacly-state photoconductivity and its nonlinear dependence on light intensity, were shown to be consistent with the presence of deep traps in this material.

Luminescence properties of the solvothermally synthesized blue light emitting Mn doped Cu2O nanoparticles

“…One violet and two blue emission peaks around 421 nm ͑2.94 eV͒, 440 nm ͑2.81 eV͒, and 469 nm ͑2.64 eV͒ are found for the sample CP1 having crystallite diameter ϳ16 nm. These emissions are expected due to the excitonic transitions from the different sub levels of the CB to the Cu d-shells of the VBs, 8,34 which will be discussed later using schematic band diagram. All the peaks were blue shifted with decreasing the size of the nanoparticles, indicating the quantum confinement effect of the excitonic transition expected for Cu 2 O nanoparticles.…”

“…Quantum confinement of electrons in the nanoparticles gives rise to the splitting of energy levels with respect to bulk. 8,46,47 Thus the relaxations of the electrons occur from the different subenergy levels of O 2p band to Cu 3d band, which give rise one violet and two blue emissions. ͑Fig.…”

“…Cu 2 O has a cubic structure with a = 4.269 Å, 7 and its p-type conductivity arises from copper vacancies which introduce an acceptor level 0.4 eV above the valence band ͑VB͒. 8 Bulk cuprous oxide ͑Cu 2 O͒ has direct forbidden bandgap of 2.17 eV. 9 The lowest of the conduction band ͑CB͒ and the top of the VB have the same parity, so that electric dipole transition between them is forbidden.…”

Low temperature growth technique for nanocrystalline cuprous oxide thin films using microwave plasma oxidation of copper

“…In addition, the Cu 2 O and CuO nanosystems have great potential for photo-activated hydrogen production, a key solution for the clean and recyclable H 2 energy. There are several reports on the growth, characterization and applications of copper 2 oxides, however, the electrical characteristics of the copper oxide films are strongly influenced by the preparation methods [3]. There are numerous reports on the exploitation of Cu 2 O as an active layer for solar cells [4][5].…”

Electrodeposited Cu2O Thin Films for Fabrication of CuO/Cu2O Heterojunction

“…Most of the techniques produce p-type conducting thin films. Many theoretical and experimental studies (Guy, 1972;Pollack & Trivich, 1975;Kaufman & Hawkins, 1984;Harukawa et al, 2000;Wright & Nelson, 2002;Paul et al, 2006) have been revealed that the Cu vacancies originate the p-type conductivity. However, electrodeposition (Siripala & Jayakody, 1986, Siripala et al, 1996Wijesundera et al, 2000;Wijesundera et al, 2006) of Cu 2 O thin films in a slightly acidic aqueous baths produce n-type conductivity.…”