Table 1.

Summary of fluorination results

Ratios of reaction gases, sccm	Sample temperature, °C	Defect density, per Å2	Percentage of F atoms with covalent bonds
99 He:1 F2	200	9.4  × 10−7	18.7  ± 1
99 He:1 F2	250	5.0  × 10−5	19.2  ± 1
99 He:1 F2	300	1.4  × 10−4	17.3  ± 1
98 He:1 HF:1 F2	23	4.2  × 10−5	11.5  ± 1

A summary of the results for the different fluorination conditions. The reaction times were 2 min for the uncatalyzed fluorination and 10 min for the sample treated with HF. Although there is a noticeable increase in fluorine adatoms with temperature for the uncatalyzed samples, the ratio of ionic to covalent C–F bonds remains relatively constant. However, fluorination with HF shows a reduced percentage of covalent bonds. For comparison, the density of naturally occurring defects observable by the STM on freshly cleaved graphite was always less than 5⁻⁸ per Ų.