Deuterium atom interaction with diamond (100) studied by X-ray photoelectron spectroscopy

Atomic and electronic structure of the diamond (100) surface: Reconstructions and rearrangements at high hydrogen coverage

“…15 Scanning tunnelling microscopy ͑STM͒ studies 7,19 confirm the ͑2ϫ1͒ reconstruction, and show rows of surface dimers. Hamza et al 15 and Lee and Apai 17 found that the ͑1ϫ1͒ pattern could be recovered by dosing the sample with atomic H or D. In contrast, Thomas et al 16 and Smentkowski et al 18 found that the ͑2ϫ1͒ pattern persisted even for very heavy dosing. It is perhaps noteworthy that oxygen, which is a common impurity, appears to stabilize the ͑1ϫ1͒ symmetry 15,16 -possible atomic structures in the presence of adsorbed O have been given by Thomas et al.…”

“…Typically, annealing of a cleaned and polished diamond sample to a temperature TϽ1000 K yields a ͑1ϫ1͒ symmetry, as observed by LEED. [15][16][17][18] On heating the sample to Tϳ1400 K, a surface reconstruction takes place producing a ͑2ϫ1͒ LEED pattern [15][16][17][18] and correlating with the desorption of hydrogen. 15 Scanning tunnelling microscopy ͑STM͒ studies 7,19 confirm the ͑2ϫ1͒ reconstruction, and show rows of surface dimers.…”

Energetic deuterium and helium irradiation effects on chemical structure of CVD diamond

“…The peak position and the FWHM of the isotropic graphite C1s peak were 284.4 and 1.3 eV, respectively. The XPS spectrum of the isotropic graphite showed a p-p à transition resulting, at approximately +6 eV above the C1s binding energy [5,6]. This p-p à transition was never observed for the pretreated diamond sample.…”

“…In other words, the C1s peaks in the D þ 2 irradiation were located at higher energy than that in the He þ irradiation. This indicates that C-D bond formation between carbon atoms and the trapped deuterium atoms was induced by D þ 2 irradiation because the formation of C-D bond results in a decrease in the electron population of carbon atom, and also an increase of the binding energy of the C1s level [6,9,10]. In addition, the sp 3 /(sp 3 + sp 2 ) ratio was almost constant.…”

“…That is, carbon atoms in the diamond received sufficient energy from energetic ions to disorder the diamond structure. Then, it is expected that the energy would be also used for relaxation of the sp 3 bonds of the carbon atom to sp 2 bonds because diamond structure is less stable thermodynamically than graphite (the free energy of formation of diamond is 2.90 kJ mol À1 greater than graphite) [6]. The disordering and relaxation of the diamond structure occurred simultaneously and eventually achieved the equilibrium state during the ion irradiation.…”