RETRACTED ARTICLE: Enhancement of the blue photoluminescence intensity for the porous silicon with HfO2 filling into microcavities
Authors: Zhengran Wu
Weideng Sun
Ran Jiang
Xianghao Du
Zuyin Han
Journal: Scientific Reports (2015)
Discipline: Multidisciplinary
Keywords: HfO2; microcavities; photoluminescence; silicon; defect levels
Affiliations: School of Physics, Shandong University, Jinan 250100, China.

Abstract:  With HfO2 filled into the microcavities of the porous single-crystal silicon, the blue photoluminescence was greatly enhanced at room temperature. On one hand, HfO2 contributes to the light emission with the transitions of the defect levels for oxygen vacancy. On the other hand, the special filling-into-microcavities structure of HfO2 leads to the presence of ferroelectricity, which greatly enhances the blue emission from porous silicon. Since both HfO2 and Si are highly compatible with Si-based electronic industry, combined the low-cost and convenient process, the HfO2-filled porous Si shows a promising application prospect. 

Retracted: Yes

PubPeer comments:
 Figure 2A showed different gating for cell frequency calculation. Since the manuscript performed statistical comparison on the frequency in Figure 2B, the gatings should all be the same. Could the authors please explain? ![file] , 
 #1 I am not entirely sure what the concern is here. Are we to infer from the blue box around one of the panels that one particular condition is the odd-one-out? , 
 #2 The authors wanted to calculate the cell frequency of Foxp3+ CD25+ cells so that they drew a specific gating to indicate the portion for Foxp3+ CD25+. However, since the gating is actually arbitrarily selected, you need to keep the gating condition  identical in all the FACS figures that one wishes to compare between. Usually, to make a solid comparison, people would run all samples in one batch, so that the software itself would maintain the same gating. A difference in the gating condition not only makes the calculation of the cell frequency meaningless, but also indicates that its likely not run in the same batch (which is fine sometimes). , 
 #3 I can t see the indication that the Foxp3+ or CD25+ cut-off criteria are *different* between the 5 right-hand panels in the FIgure. , 
 #4 ![file] The red line indicates the same Foxp3+ cut-off criteria as it should be. As you can see, if gated correctly, the cell frequency for Foxp3+ CD25+ would become lower, estimated around 16 (instead of 19.2), which would show a ~20 % difference (decrease in frequency) compared to the rest, and make the results look less consistent. , 
 Here we attach the complete image for Figure 2a, in which the top two panels were cropped by the anonymous commenter for unknown reasons. We are also obligated to point out that Figure 2b represents mRNA expression, not the statistical comparison of protein expression data in Figure 2a, evidencing misinterpretation by the commenter. The purpose of the experiment was to determine whether IL-21 inhibits TGF-u03b2-upregulated Foxp3 and induces IL-17 expression. The culture conditions in Figure 2a were clearly labeled on the right side of the FACS plots. The presence of TGF-u03b2 in the culture (the third row of panels from the top) resulted in robust FOXP3 staining, which was strongly inhibited by either IL-6 or IL-21. In contrast, the combination of IL-6 or IL-21 with TGF-u03b2 greatly enhanced IL-17 expression. The gating for FOXP3 in the bottom right figure highlighted by the commenter, in which the cells were cultured with TGF-u03b2, IL-21 and IL-23, is consistent with the cells cultured under IL-21 or IL-6 conditions (top two right panels), which were somehow left out by the commenter. It is obvious that IL-23, in the presence of TGF-u03b2 and IL-6 or IL-21, further enhanced IL-17 (Y-axis) staining at the left panel, without affecting FOXP3 downregulation. In a nutshell, we, as well as original reviewers and numerous readers over the past 13 years (this article has been cited 1079 times) do not see any scientific concerns over this figure. Moreover, the exact same conclusion was independently reached by another research article published in the same issue of Nature. -Roza Nurieva and Chen Dong ![file] ,