Duplication earns retraction for nanomaterials paper that had already been corrected

After earning an erratum shortly after publication in 2009, a paper in Applied Physics Letters has now been retracted for the “regrettable mistake” of duplicating an earlier paper by the researchers.

Here’s the notice for “Broadband and omnidirectional antireflection from conductive indium-tin-oxide nanocolumns prepared by glancing-angle deposition with nitrogen:”

The authors wish to retract this paper ¹ due to overlap of content with their previously published paper in Advanced Materials, ²including duplicated SEM images and measurement data. The regrettable mistake was a result of mishandling of experimental data with high resemblance. For that, the authors apologize to the readers and the editorial office of Applied Physics Letters for any confusion caused.

Here’s the text from the erratum, which involved the same figures:

In the published version of Fig. 2 , the data were mistaken from the sample presented in Ref. 1 . The correct figure is given below with corresponding SEM images (Figs. 1(a) and 1(b) ). This does not change any of our results. The authors apologize to the readers of Applied Physics Letters for any confusion that this might have caused.

The paper cited in the retraction was originally published in Advanced Materials. Here’s the abstract:

Highly-oriented indium tin oxide nanocolumns are prepared by glancing-angle deposition with nitrogen. The tapered column profiles, which function as a graded-refractive-index layer, offer superior antireflective characteristics. The nanostructured material serves as the conductive antireflective layer for GaAs solar cells, demonstrating a viable efficiency-boosting strategy for next-generation photovoltaics.

And the abstract of the retracted paper, which has been cited 45 times, according to Thomson Scientific’s Web of Knowledge:

Characteristic formation of highly oriented indium-tin-oxide (ITO) nanocolumns is demonstrated using electron-beam evaporation with an obliquely incident nitrogen flux. The nanocolumn material exhibits broadband and omnidirectional antireflective characteristics up to an incidence angle of 70° for the 350–900 nm wavelength range for both s– and p-polarizations. Calculations based on a rigorous coupled-wave analysis indicate that the superior antireflection arises from the tapered column profiles which collectively function as a gradient-index layer. Since the nanocolumns have a preferential growth direction which follows the incident vapor flux, the azimuthal and polarization dependence of reflectivities are also investigated. The single ITO nanocolumn layer can function as antireflection contacts for light emitting diodes and solar cells.

Corresponding author Peichen Yu declined to comment.

Hat tip: Rolf Degen