This paper presents the fabrication and characterization of high-quality mono- and bilayer graphene (MLG and BLG) devices on single-crystal hexagonal boron nitride (h-BN) substrates. The study demonstrates that graphene on h-BN exhibits enhanced carrier mobility, reduced carrier inhomogeneity, and lower intrinsic doping compared to graphene on SiO₂. The use of h-BN as a substrate offers significant advantages over traditional SiO₂, including a lower surface roughness, reduced scattering from charged impurities, and a smaller lattice mismatch with graphene. These properties make h-BN an ideal substrate for high-quality graphene electronics. The research describes a mechanical transfer process for fabricating graphene-on-BN devices, which involves exfoliating h-BN and graphene onto a suitable substrate, transferring them to a target substrate, and then characterizing the resulting devices. The quality of the graphene-on-BN devices is evaluated through various transport measurements, including magnetotransport and conductivity measurements. The results show that the graphene-on-BN devices exhibit high-quality electronic properties, with a narrow resistivity peak at the charge neutrality point and a high mobility. The study also compares the performance of graphene-on-BN with that of graphene on SiO₂, showing that the h-BN substrate significantly improves the electronic properties of graphene. The results suggest that h-BN is a promising alternative to SiO₂ for graphene-based electronics, as it provides a more stable and less scattering environment for graphene. The research highlights the potential of h-BN as a substrate for future graphene-based electronic devices, enabling the development of more complex graphene heterostructures. The findings also suggest that the use of h-BN as a substrate can lead to improved performance in graphene-based devices, particularly in high-temperature and high-electric field applications.This paper presents the fabrication and characterization of high-quality mono- and bilayer graphene (MLG and BLG) devices on single-crystal hexagonal boron nitride (h-BN) substrates. The study demonstrates that graphene on h-BN exhibits enhanced carrier mobility, reduced carrier inhomogeneity, and lower intrinsic doping compared to graphene on SiO₂. The use of h-BN as a substrate offers significant advantages over traditional SiO₂, including a lower surface roughness, reduced scattering from charged impurities, and a smaller lattice mismatch with graphene. These properties make h-BN an ideal substrate for high-quality graphene electronics. The research describes a mechanical transfer process for fabricating graphene-on-BN devices, which involves exfoliating h-BN and graphene onto a suitable substrate, transferring them to a target substrate, and then characterizing the resulting devices. The quality of the graphene-on-BN devices is evaluated through various transport measurements, including magnetotransport and conductivity measurements. The results show that the graphene-on-BN devices exhibit high-quality electronic properties, with a narrow resistivity peak at the charge neutrality point and a high mobility. The study also compares the performance of graphene-on-BN with that of graphene on SiO₂, showing that the h-BN substrate significantly improves the electronic properties of graphene. The results suggest that h-BN is a promising alternative to SiO₂ for graphene-based electronics, as it provides a more stable and less scattering environment for graphene. The research highlights the potential of h-BN as a substrate for future graphene-based electronic devices, enabling the development of more complex graphene heterostructures. The findings also suggest that the use of h-BN as a substrate can lead to improved performance in graphene-based devices, particularly in high-temperature and high-electric field applications.