This paper presents the fabrication and characterization of field-effect transistors (FETs) based on few-layer black phosphorus crystals. The authors successfully fabricated FETs with drain current modulation of up to \(10^5\) and well-developed current saturation, demonstrating reliable transistor performance. The sample mobility was found to be thickness-dependent, with the highest value of ~1000 cm\(^2\)/V·s achieved at a thickness of ~10 nm. The results highlight the potential of black phosphorus thin crystals as a new two-dimensional material for future applications in nano-electronic devices. The band structure of bulk black phosphorus, verified by ARPES and ab initio calculations, shows a direct band gap of ~0.2 eV. The FETs exhibit ambipolar behavior, with drain current modulation and mobility values comparable to or better than those of other layered materials like MoS\(_2\). The thickness dependence of these metrics suggests that thinner samples are more susceptible to charge impurities, leading to lower mobilities. The study also explores the temperature dependence of carrier mobility, finding that it is limited by charge impurity scattering at low temperatures and electron-phonon scattering at high temperatures. Overall, the work demonstrates the promising potential of black phosphorus in high-speed field-effect devices.This paper presents the fabrication and characterization of field-effect transistors (FETs) based on few-layer black phosphorus crystals. The authors successfully fabricated FETs with drain current modulation of up to \(10^5\) and well-developed current saturation, demonstrating reliable transistor performance. The sample mobility was found to be thickness-dependent, with the highest value of ~1000 cm\(^2\)/V·s achieved at a thickness of ~10 nm. The results highlight the potential of black phosphorus thin crystals as a new two-dimensional material for future applications in nano-electronic devices. The band structure of bulk black phosphorus, verified by ARPES and ab initio calculations, shows a direct band gap of ~0.2 eV. The FETs exhibit ambipolar behavior, with drain current modulation and mobility values comparable to or better than those of other layered materials like MoS\(_2\). The thickness dependence of these metrics suggests that thinner samples are more susceptible to charge impurities, leading to lower mobilities. The study also explores the temperature dependence of carrier mobility, finding that it is limited by charge impurity scattering at low temperatures and electron-phonon scattering at high temperatures. Overall, the work demonstrates the promising potential of black phosphorus in high-speed field-effect devices.