Low-Power Laser Graphitization of High Pressure—High Temperature Nanodiamond Films
, Tatyana N. Mogileva 1, Arseniy E. Fateev 1, Nicholas A. Nunn 2,3, Olga A. Shenderova 2 and Gennady M. Mikheev 1,*Round 1
Reviewer 1 Report
Authors report an experimental study on the graphitization of nanodiamonds induced by low-power laser beam. The English form is fluent and easy to understand. The topic looks to be properly inserted into the existing literature. Experimental setup is properly detailed, results properly presented and discussed. The outcomes of the work present important physical insights and provide a new route to control the diamond/graphite phase transition under specific experimental conditions.
I therefore recommend the publication of the manuscript as it is.
Author Response
Response to Reviewer 1 Comments
Point: Authors report an experimental study on the graphitization of nanodiamonds induced by low-power laser beam. The English form is fluent and easy to understand. The topic looks to be properly inserted into the existing literature. Experimental setup is properly detailed, results properly presented and discussed. The outcomes of the work present important physical insights and provide a new route to control the diamond/graphite phase transition under specific experimental conditions.
I therefore recommend the publication of the manuscript as it is.
Response: We are very grateful to the Reviewer for his/her evaluation of the manuscript. Though the Reviewer recommended the publication of the manuscript as it is, in the revised manuscript we have made minor changes that improve the presentation.
Reviewer 2 Report
general problem of authors
XRD you are measure diffractograms not spectra. You detect angle vs. intensity and there is no energy for spectra!
Change all XRD spectra in XRD diffractograms!
fig. 2 you measure the HP-HT NDs as powder, therefore you get a diffractogram for a polycrystalline diamont - here add the data for crystal pattern you get from PDF-File ore COD file, you use!
Better index the peaks in fig. 2 with the miller indices. What about of measured diffractograms of samples in fig 1a and b?
Fig. 3a is a bad quality of measuring. In this magnification-scanning range you must get sharper surface topography, measure with slower scan speed.
The SEM picture in fig. 3b shoud be chanched, so that the magnification will be nearly the same.
Try to add in fig 7 an additional graph, so you have always four graphs, it looks like better in comparing fig. 10.
With this changes the article will be better to understand.
Author Response
Response to Reviewer 2 Comments
We are very grateful to the Reviewer for his/her detailed and thoughtful evaluation of the manuscript and, especially, for pointing out issues that have not been clearly addressed and lead to misunderstanding. In the revised manuscript, we have made changes that improve the presentation and directly address the Reviewer’s concerns.
Please find below our point-to-point reply to the Reviewer’s comments and criticism.
Point 1: XRD you are measure diffractograms not spectra. You detect angle vs. intensity and there is no energy for spectra! Change all XRD spectra in XRD diffractograms!
Response 1: We agree with this point and changed all XRD spectra in XRD patterns (see lines 75,82,84-86,88,89 and the figure 2 caption in the revised manuscript).
Point 2: fig. 2 you measure the HP-HT NDs as powder, therefore you get a diffractogram for a polycrystalline diamont - here add the data for crystal pattern you get from PDF-File ore COD file, you use!
Response 2: We added the data from the powder diffraction file (PDF 00-006-0675) of diamond in figure 2 for one to compare it with our data. We also added this information in the text (line 90) of the revised manuscript.
Point 3: Better index the peaks in fig. 2 with the miller indices. What about of measured diffractograms of samples in fig 1a and b?
Response 3: We indexed the peaks of PDF in figure 2 with the miller indices. The XRD pattern of the sample in figure 1a (HP-HT nanodiamond film) is identical to that presented in figure 2 (HP-HT nanodiamond powder) but with a lower signal/noise ratio comparing to the powder XRD pattern. This is the reason why we included the XRD pattern of the powder rather than film.
Point 4: Fig. 3a is a bad quality of measuring. In this magnification-scanning range you must get sharper surface topography, measure with slower scan speed.
Response 4: Unfortunately, we couldn’t get a better quality AFM image of the film. However, we took into account the comment and tried to improve the sharpness of the image, so the nanodiamond particle edges were clearer. In our opinion, the quality of the image is enough to estimate the characteristic size of the observed particles. See changes in lines 96-98 of the revised manuscript.
Point 5: The SEM picture in fig. 3b shoud be chanched, so that the magnification will be nearly the same.
Response 5: We have changed the SEM image in figure 3b to one with the largest magnification we have so that the magnification in the figure 3a is nearly the same. Note that we changed the order of the images in figure 3 for the better perception, so the SEM image is now in figure 3a and the AFM image is now in figure 3b. See changes in lines 96-98 of the revised manuscript.
Point 6: Try to add in fig 7 an additional graph, so you have always four graphs, it looks like better in comparing fig. 10.
Response 6: We restructured figure 7 in order to make it look better.
Reviewer 3 Report
This is an acceptable paper where the authors give details of the observation of graphitization and blackening of diamond films. Curiously this occurs when they scan a low power laser spot across the film but not necessarily when the laser spot is stationary. The difference is attributed to inhomogeneous distribution of impurities most likely associated with nickel, nitrogen and associated complexes.
The studies are quite extensive and includes absorption, emission, X-ray diffraction, Raman spectroscopy, Atomic Force microscopy and SEM.
Some minor points could be clearer.
- The optical emission given in Figure 4 is of aqueous suspension. Presumably this is in the preparation stage prior to drying. Why is this preferred rather than that of dried film?
- The authors show spectrum of these aqueous films. Later they show they are capable of measuring the Raman spectrum of presumably the dried film but not the spectrum.
- The describe green emission but do not attribute this to any of the spectral features shown in Figure 4. Can the spectrum not be measured?
- They make several references to NV centers but there is no evidence of such centers. Should state why this is included. (a guide to what might be expected?)
- The introduction to NV is correct with ground states 3A2 and 2E but then use 3E for NV0 rather than 2E. Also to be technically correct the transition associated with the neutral center has been shown to be 2E – 2A2 (PRB, 87, 155209, (2013)) rather than 2E – 2A1. This change can be made without affecting their discussion.
Author Response
Response to Reviewer 3 Comments
We are very grateful to the Reviewer for his/her detailed and thoughtful evaluation of the manuscript and, especially, for pointing out issues that have not been clearly addressed and lead to misunderstanding. In the revised manuscript, we have made changes that improve the presentation and directly address the Reviewer’s concerns.
Please find below our point-to-point reply to the Reviewer’s comments and criticism.
Point 1: The optical emission given in Figure 4 is of aqueous suspension. Presumably this is in the preparation stage prior to drying. Why is this preferred rather than that of dried film?
Response 1: Indeed, at the very first step we had aqueous suspensions of HP-HT nanodiamonds of different concentrations. It is important to have optical emission of initial samples that is why we presented the luminescence spectra of an aqueous HP-HT nanodiamond suspension. We also measured the luminescence spectra of HP-HT nanodiamond film, with them being identical to that of aqueous HP-HT nanodiamond suspension. According to that, we added in the revised manuscript the state that all the spectra in Figure 4b,c,d are identical to that of HP-HT nanodiamond film presented in Figure 1a (see lines 124-125 in the revised manuscript).
Point 2: The authors show spectrum of these aqueous films. Later they show they are capable of measuring the Raman spectrum of presumably the dried film but not the spectrum.
Response 2: As we noted above, the spectra in Figure 4b,c,d are identical to that of HP-HT nanodiamonds film. As to the Raman spectra, it was important to compare the Raman spectra of the initial film (Figure 1a) and the modified film (Figure 1b). Therefore, we present the Raman spectra for the film rather than suspension.
Point 3: The describe green emission but do not attribute this to any of the spectral features shown in Figure 4. Can the spectrum not be measured?
Response 3: We tried to measure the spectrum of green emission. Unfortunately, since the emission is very weak and short in time we were unable to measure its spectrum.
Point 4: They make several references to NV centers but there is no evidence of such centers. Should state why this is included. (a guide to what might be expected?)
Response 4: As noted in line 260 of the revised manuscript, in the studied HP-HT nanodiamonds , the [N-V]- centers were not specifically created and we agree that there is no evidence that such centers are present in the films. We refer to NV centers as an example of variety of impurity centers in HP-HT nanodiamonds. The presence of such centers would explain the mechanism of low-power laser blackening accompanied with the emission. Another example of such impurity centers are Ni and N centers the presence of which in the studied HP-HT nanodiamond film is evident from figure 4. We mention it in the lines 262-265 of the revised manuscript.
Point 5: The introduction to NV is correct with ground states 3A2 and 2E but then use 3E for NV0 rather than 2E. Also to be technically correct the transition associated with the neutral center has been shown to be 2E – 2A2 (PRB, 87, 155209, (2013)) rather than 2E – 2A1. This change can be made without affecting their discussion.
Response 5: We agree with this comment and appreciate it much. We changed the transition 3E - 2A1 to the transition 2E - 2A2 in the text of the revised manuscript and added the reference [42]. See all changes in the lines 249-252,257 of the revised manuscript.
