Ohmic Contact of Pt/Au on Hydrogen-Terminated Single Crystal Diamond

Round 1

Reviewer 1 Report

This paper investigated the nature of Pt/Au ohmic contact on hydrogen-terminated single crystal diamond layers with various treatment conditions. Carrier transport mechanism was investigated using temperature-dependent current-voltage (T-I-V) measurement. The results suggest that the template exhibits obvious ohmic properties. Also, the authors analyzed thermal stability. The reviewer suggests accepting this manuscript for publication in Coatings after the following questions were well addressed.

1. The work used Pt/Au alloys to make ohmic properties in SCD films. Please find out the phase diagram of Pt/Au system. Over 400 ^oC, Pt and Au coexist as an alloy. Therefore, the title should be changed as Pt/Au.
2. The authors ignore recent work concerning the investigation of Pt/Au Ohmic contact. I I recommend the authors to cite some recent works related to transport mechanism of Pt/Au Ohmic contact, which will be helpful for the readers to know the state-of-the-art of this topic.
3. The reviewer suggest that the authors stress why hydrogen-terminated surface in SCD is important to ripen doping process of diamond-based electronic devices in introduction section, which will be very helpful to understand the readers.
4. The reviewer request that the authors provide 2theta-theta data of XRD, which proves the phase of SCD. Furthermore, the authors have to compare the value of FWHM in SCD with other literatures. The readers cannot accept the author’s state that the crystal quality of SCD is good without it. Truly, you have to consider the crystallinity as a function of SCD thickness. Also, the reviewer recommend changing the unit of degree in XRD to arcsec.
5. The authors missed the references for all the equations in the article, except for barrier height calculation.
6. Please explain the saturation current in T-I-V curves in the manuscript.
7. There is a serious error in XPS analysis. As the reviewer commented the contact consists of Pt/Au alloy, not the single Pt metal. Therefore, the sampling for XPS measurements has to be investigated as Pt/Au alloy. In this case, the band diagram has to be modified as well.
8. By international convention, XPS spectra are to be plotted with binding energy increasing to the left, not to the right, which is what you have done in Figure 6.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Pt/Au films were deposited onto H terminated (100) diamond surface and the contact resistence was measured as function of temperature in the 200-700 C interval. The manuscript is of moderate novelty and the presentation and interpretation of the results are of average quality.

It can be improved by extending with some background considerations, and by more detailed explanation of some results, e.g:

1. why (100) surface has been chosen, lines 40-41.
2. interpretation of surface roughness (0.6nm) in terms of (100) atomic surface of diamond lines 60-61.
3. "low full-width -at-half-maximum" line 65 with respect of what.
4. explanation of local minimum of contact resistance at 300 C, Figure 3.
5. E 3nm and E 70 nm Pt coincide within the error the measurement in Eq.3.
6. Additionally the English of the manuscript has to be improved, there are several sentences which sound like loan translations, e.g. "making it a great application potential in the field of..."
7. and also several typos, some of them are funny, e.g. "diffraction angel" in Fig 2a.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The reviewer satisfies the revised manuscript.