Highly-doped p-type few-layer graphene on UID off-axis homoepitaxial 4H-SiC

ABSTRACT In this report we investigate structural and electrical properties of epitaxial Chemical Vapor Deposition quasi-free-standing graphene on an unintentionally-doped homoepitaxial layer grown on a conducting 4H-SiC substrate 4° off-axis from the basal [0001] direction towards [ [11] , [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] ]. Due to high density of SiC vicinal surfaces the deposited graphene is densely stepped and gains unique characteristics. Its’s morphology is studied with atomic force and scanning electron microscopy. Its few-layer character and p-type conductance are deduced from a Raman map and its layers structure determined from a high-resolution X-ray diffraction pattern. Transport properties of the graphene are estimated through Hall effect measurements between 100 and 350 K. The results reveal an unusually low sheet resistance below 100 Ω/sq and high hole concentration of the order of 1015 cm-2. We find that the material’s electrical properties resemble those of an epitaxially-grown SiC PIN diode, making it an attractive platform for the semiconductor devices technology.