Characterization of experimental textured ZnO:Al films for thin film solar cell applications and comparison with commercial and plasmonic alternatives

Abstract

We present the comprehensive characterization of several experimental ZnO:Al films for thin film solar cell applications. The morphological and optical properties of these films are determined using traditional and new, experimental measurement techniques and results are compared to those of the commercial Asahi U-type TCO as well as samples of planar TCOs coated in silver nanoparticles. Results show that the textured ZnO:Al films provide far superior scattering to the commercial alternatives studied. Nanoparticle coated planar TCOs also show scattering enhancement with results suggesting that nanoparticle layers could be tuned to predominantly scatter light within a chosen wavelength range.

Large-Scale Deposition of Transparent Conducting Oxides by Hollow Cathode Sputtering

“…The very thick AZO sample A (3.15 m) had a haze figure of 83.7% and a measured T tot of 82.8% (artificially reduced by residual scattering). Wavelength-dependent haze measurements reveal that this sample had a haze value of almost 40% at 900 nm [12]. For these samples, haze correlated well with film thickness.…”

“…The surface morphology of two textured films (samples A and B) are shown in the SEM micrographs of Figures 4 and 5. For sample A, the RMS roughness is 130 nm [12]. The ability to control feature size means that the TCO can be tailored to either a-Si or a-Si/nc-Si module technologies.…”

Optoelectronic simulations for novel light management concepts in Cu(In,Ga)Se2 solar cells

“…In initial studies, it was verified that the AR performance is enhanced both by increasing the and decreasing the values, therefore the optimization goes on establishing a lower surface roughness limit. For these simulations, a value of 100 nm and a of 100 nm, that is in accordance with the structural features verified in wet-etch procedures of ZnO and AZO layers in acidic solutions, was applied to the 400 nm AZO layer [40][41][42] . The simulated absorption in the CIGS layer, alongside the simulated reflection, for an ultrathin reference and an ultrathin device with a random textured AZO layer device are shown in Figure 6 a).…”