We further studied the compatibility of the B4C deposition by Raman spectroscopy before and after the CVD process, as the deposition may induce strain or defects in the CNT structure that will influence the vibrational modes , see Fig. . The Raman spectra of CNTs typically exhibit three main features, the radial breathing mode (RBM), the G band, and the D band. The G band is a vibration mode that involves the stretching of the C-C bonds along the CNT axis, see Fig. . The G band frequency reflects the bond length and angle of the carbon atoms, and thus the strain and stress in the CNT. The D band intensity reflects defects and doping in CNTs, with the D peak being activated by the breathing vibrational mode of hexagonal rings necessitating a defect. The RBM is a vibration mode in which all the carbon atoms move radially in and out, like a breathing motion (Fig. ). The RBM frequency depends on the diameter, chirality, and structure of the CNT, as well as the external factors, such as strain, pressure, and temperature. It can be noted from Fig. that the CVD process shifted to the G band peak positions. G band peak center observed at 1572.4 cm -1 for the pristine CNT membrane red-shifted to 1568.9 cm -1 after the CVD process. We attribute this to the reflection of the average stress experienced by the CNT surfaces due to the film deposition. The G band to D band intensity ratio (IG/ID) which is commonly used for screening the quality of the CNTs changed from 43 to 23.5 showing that the CVD process induced modification in the CNT surface. Nevertheless, the vibrational mode analysis has several limitations despite its quick and convenient nature. The diverse attributes contributing to the vibrational band make the quantitative analysis difficult. The membrane structure, consisting of randomly oriented nanotubes with various diameters, further complicates the analysis. Despite this complexity, we suggest that the CVD process, while modifying the exterior walls as expected and needed for the film growth, exhibits good compatibility with the CNTs. This is evidenced by the preservation of structural integrity, indicated by higher G-band and lower D-band band intensities, as well as RBM. Furthermore, the intense peak from the sp 2 hybridized C-C bonds and the extra shoulder peak corresponding to the film contributions observed from the XPS measurement align with this observation. The amorphous nature of the B4C can also contribute to the loss of signal intensity. We therefore deposited a thicker B4C film on a Si wafer under the same conditions. While XRD measurement of the thicker B4C reference film on Si(100) suggests that the films are X-ray amorphous, Raman spectroscopy of the reference film indicates the presence of short-range order, as shown in Fig. . The broad peaks between 400-700 cm -1 and 800 to 1300 cm -1 are characteristic of an amorphous B4C phase with significant short range order. The fitted peak positions in the background deconvoluted curve align closely with reported values. While the peak centered at 325 cm -1 is associated with disorder activated vibrational modes , 473 cm -1 , 657 cm -1 and 831 cm -1 , 933 cm -1 and 1090 cm -1 are closer to the reported values for B4C . The prominent peak observed at 473 cm -1 is indicative of the vibrational modes resulting from atomic displacements within the icosahedra structure. The minor peak at 1526 cm -1 , is assigned as the G-band of amorphous carbon, indicating the presence of some amount of amorphous carbon. The C1s core level XPS spectra (Fig. XRD analysis of the CNT membranes before and after the CVD process reveals a peak that corresponds to the 002-crystal plane of the CNTs (Fig. ). Interestingly, the FWHM for the 002-peak reduced from 6.2 to 5.7 degrees after the deposition, indicating an increase in the average diameter of the nanotubes in the composite form. Since intratube and intertube contributions cause peak broadening, the standard Scherrer equation is not suitable for estimating tube diameter without resolving these components through curve fitting. While Raman spectroscopy (Fig. ), shows a decrease in the IG/ID ratio, indicating surface modification after deposition, XRD analysis suggests that the CVD process did not modify the CNTs lattice. Instead, it apparently shows an increase in the average diameter in composite form, indicating a possible lattice matched interface. From the characterization above, we conclude that the B4C film grows on the CNTs without destroying their structure. B4C's built up of B icosahedra is known for its octet rule violation meaning that it does not have enough valence electrons to form the standard two-electron twocenter bond within the icosahedra, resulting in more than two atoms sharing a pair of electrons. We speculate that the electron deficient boron icosahedra interacts with the outof-plane π-cloud of the rolled-up graphene-like structure of the CNTs. Electron diffraction measurement presented in Fig. shows a broad frequency band centered around the theoretical 2-21 and 4-32 reflections of B4C R-3m, confirming short range order. Interestingly, the 1-14 CNT reflection overlaps with the 4-32 B4C reflection at a 0.3% mismatch, a prerequisite for epitaxy. The observed reduction in the FWHM of the 002-plane peak (Fig. ), suggesting an apparent increase in average diameter, is consistent with the observation of near surface lattice matching, which allows some more X-rays to scatter coherently and resembles an increase in the average number of walls in the distribution. The ability to control the film thickness during the CVD process provides pore size tunability.