Lattice damage in 9-MeV-carbon irradiated diamond and its recovery after annealing

Abstract

We have studied the radiation damage in diamond as a function of layer depth upon self-ion implantation with 9-MeV carbon ions and its recovery after annealing at 1000 • C. Raman and photoluminescence spectra show substantial damage of the lattice, namely, amorphization, neutral vacancies, and interstitial defects. Damage is maximum in the stopping layer at a depth of 4 µm. After annealing there is some recovery of the lattice, but the residual damage increases with fluence, up to about 2 × 10 16 ions/cm 2. At this fluence the stopping layer becomes highly disordered and does not heal with annealing. Surprisingly, for higher fluence values, of about 5 × 10 16 ions/cm 2 , there is almost no residual damage. After full amorphization is reached, the layers appear to recrystallize by solid phase epitaxy (SPE), using the pristine diamond layers underneath as a template. These results prove that graphitization of diamond after annealing can be avoided in deeply buried layers, implanted at fluences much higher than expected. High fluences, in fact, can lead to high quality diamond layers. If SPE can be confirmed, it would have a great interest for diamond device applications, as it allows for higher doping levels. ion irradiation 9-MeV C ions micro-spectroscopy 10 μm stopping layer Figure 1: Scheme of the experimental procedure. A diamond crystal was implanted with 9-MeV 12 C 3+ ions at different fluences and then annealed at 1000 • C for 1 h. Optical microspectroscopy measurements were performed both after implantation and after annealing. The inset shows an actual transmission light micrograph of an implanted stripe as seen from the top sample surface (fluence 130 × 10 14 ions/cm 3).

Raman scattering in diamond irradiated with high-energy xenon ions

“…More significant electronic energy losses, as in [37], did not manifest themselves in defect formation. The same dependence was noted by all researchers of ion-irradiated diamonds (see, for example, [4,14,[38][39][40]). It should be noted, that the depth of maximum defect formation determined experimentally from the shift and FWHM of the 1332 cm -1 line was approximately 1.0 μm closer to the surface than predicted by SRIM -10.45 μm.…”

Layer-Spacing-Enlarged MoS2 Superstructural Nanotubes with Further Enhanced Catalysis and Immobilization for Li–S Batteries

“…Strangely, there is no such carbon layer found in the HRTEM image of the as-prepared MoS 2 , as shown in Figure S2, which may be the unstable fragmentary carbon structure formed after the solvothermal reaction and cannot be identified by HRTEM. 24 Figure S6 gives the comparison of electrical conductivity between MoS 2 and LE-MoS 2 , and the conductivities of LE-MoS 2 and S/LE-MoS 2 are enhanced up to 1328 and 174 S m −1 , much higher than those of MoS 2 (547 S m −1 ) and S/MoS 2 (43 S m −1 ), which suggests that the carbon intercalation after annealing is crucial to enhance the conductivity.…”

Probing the Nanostructure of Neutron-Irradiated Diamond Using Raman Spectroscopy

“…Different tentative attributions have been formulated for the 1430 (1450) and 1480 (1501) cm −1 peaks [ 14 ], involving vacancy [ 41 , 65 ], intrinsic/nitrogen interstitial defects [ 67 , 68 ], or a vacancy or a divacancy surrounded by conjugated single and double carbon–carbon bonds (the R4/W6 center) [ 21 , 69 ]. Recent calculations [ 70 ] based on the B3LYP hybrid implementation of density functional theory [ 71 ] show the absence of peaks in the region of 1490 cm −1 in the spectra of both divacancy V 2 and V—C=C—V.…”