Patent ID: 7700064

Claim:
A single carbon solid fiber which has (1) a metal element content of no more than 50 ppm and (2) a fiber diameter of 0.001 to 2 μm and (3) substantially no branched structure which is seen through an electron microscope, wherein the half-value width of the Raman band at 1,580 cm −1 measured by Raman spectroscopy of the exterior surface of the carbon fiber is 25 cm −1 or less, wherein the R value defined by the following equation measured by Raman spectroscopy of the exterior surface of the carbon fiber is 0.08 to 0.2, R=I 1355 /I 1580 wherein I 1355 and I 1580 are the strengths of the Raman band at 1,355 cm −1 and 1,580 cm −1 , respectively, wherein streak-like irregularities extending in the fiber axial direction are existent on the exterior surface of the fiber, wherein the ratio (L/D) of the fiber length (L) to the fiber diameter (D) is 2 to 1.000, wherein the carbon fiber is made up of graphite which is composed of a plurality of graphenes and the graphenes are bonded together by a carbon bridge at the end of the carbon fiber, wherein the graphene surface of a graphite layer is oriented in the fiber axial direction, wherein the distance (d 002 ) between adjacent graphite sheets is in the range of 0.335 to 0.360 nm, and the thickness (Lc) of graphenes is in the range of 1.0 to 150 nm according to wide-angle X-ray measurement.