Optical Absorption of Cuprous Oxide

Abstract

The relative optical absorption coefficient o, of polycrystalline slabs of cuprous oxide was measured at 295'K, 77'K, and 4.2'K. At 4.2'K, n is proportional to La is the wave number. At 77'K an additional component appears, so that n=ai+ces, with n&~Pa -E&g& and as~Po -E2]&. This is attributed to indirect transitions to exciton levels, in agreement with a theory by Elliott. The ratio of the integrated absorption coeKcient of the first two exciton lines, after corrections for the background were applied, is also in satisfactory agreement with the Elliott theory.

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

“…The spectrum shows the band edge at 2.01 eV, with the appearance of a small peak at 2.14 eV, which corresponds to the first allowed green excitonic peak of Cu 2 O. These values are in close agreement with the previous reports on bulk Cu 2 O [12]. The presence of the Cu 2 O phase formed during the 10 min oxygen plasma exposure can be again verified using the reflectance spectra in the inset of figure 2.…”

Strong Efficiency Improvements in Ultra‐low‐Cost Inorganic Nanowire Solar Cells

“…The absorption coefficient is observed to increase slowly at energies just above the bandgap, as exciton transitions at these energies are parity forbidden and must be mediated indirectly by phonons. [ 18 ] The fi rst allowed transition occurs at approximately 2.6 eV, which is seen to result in a sharp increase in absorption at a wavelength around 475 nm. For various Cu 2 O thicknesses, the maximum J SC was calculated by multiplying the absorption profi le by the standard AM 1.5G solar photon fl ux (100 mW cm − 2 ) and integrating over all wavelengths.…”

Oxidation of Cu on ZnO(0001)-Zn: Angle-Resolved Photoelectron Spectroscopy and Low-Energy Electron Diffraction Study

“…In the present study, information on the conduction band structure is not obtained. If we assume that the band gaps of both ZnO and Cu 2 O have the same values as those of bulk materials, i.e., 3.37 eV [1] and 2.1 eV [4][5][6][7], respectively, the conduction-band min- …”

“…Since ZnO is a ntype semiconductor, fabrication of a p-n heterojunction by deposition of p-type semiconductors on the ZnO film, or vise versa, is essential for these applications. Cu 2 O, a natural p-type semiconductor with a band-gap energy of 2.0-2.2 eV [4][5][6][7], is expected to be one of candidates to realize a high performance photovoltaic cell in combination with n-type ZnO, because a high conversion efficiency of Cu 2 O is theoretically predicted [8]. However, p-Cu 2 O/n-ZnO cells fabricated so far have only achieved the efficiency below 2% [5,9,10].…”