This paper reports the experimental observation of the quantum Hall effect (QHE) and Berry's phase in high mobility single-layer graphene. The study demonstrates that graphene exhibits a half-integer QHE, which is distinct from the conventional integer QHE observed in other 2D systems. This unique behavior arises from the exceptional electronic structure of graphene, characterized by a linear dispersion relation and vanishing carrier mass near the Dirac point. The half-integer QHE is attributed to the topological nature of the graphene band structure, which leads to a non-zero Berry's phase for the electron wavefunction. The experiments were conducted on high-quality graphene samples, which were extracted from Kish graphite and transferred onto Si wafers with a SiO₂ coating. The samples were characterized using gate voltage modulation to control the carrier density and mobility. The results show that the QHE in graphene is distinct from conventional QHEs, as the quantization condition is shifted by a half-integer. This is due to the particle-hole symmetry and the unique electronic structure of graphene. The study also provides evidence for the non-zero Berry's phase in graphene, which was confirmed through magneto-oscillation measurements. The Berry's phase was extracted from the SdH fan diagram, where the phase shift was found to be close to 0.5, indicating the presence of Dirac particles. Additionally, the effective carrier mass was determined from the temperature dependence of the SdH oscillations, showing a strong suppression near the Dirac point. The results highlight the unique properties of graphene and its potential for novel electronic and magneto-electronic device applications. The study provides a deeper understanding of the quantum transport phenomena in graphene and opens up new avenues for research in mesoscopic transport and quantum electronics.This paper reports the experimental observation of the quantum Hall effect (QHE) and Berry's phase in high mobility single-layer graphene. The study demonstrates that graphene exhibits a half-integer QHE, which is distinct from the conventional integer QHE observed in other 2D systems. This unique behavior arises from the exceptional electronic structure of graphene, characterized by a linear dispersion relation and vanishing carrier mass near the Dirac point. The half-integer QHE is attributed to the topological nature of the graphene band structure, which leads to a non-zero Berry's phase for the electron wavefunction. The experiments were conducted on high-quality graphene samples, which were extracted from Kish graphite and transferred onto Si wafers with a SiO₂ coating. The samples were characterized using gate voltage modulation to control the carrier density and mobility. The results show that the QHE in graphene is distinct from conventional QHEs, as the quantization condition is shifted by a half-integer. This is due to the particle-hole symmetry and the unique electronic structure of graphene. The study also provides evidence for the non-zero Berry's phase in graphene, which was confirmed through magneto-oscillation measurements. The Berry's phase was extracted from the SdH fan diagram, where the phase shift was found to be close to 0.5, indicating the presence of Dirac particles. Additionally, the effective carrier mass was determined from the temperature dependence of the SdH oscillations, showing a strong suppression near the Dirac point. The results highlight the unique properties of graphene and its potential for novel electronic and magneto-electronic device applications. The study provides a deeper understanding of the quantum transport phenomena in graphene and opens up new avenues for research in mesoscopic transport and quantum electronics.