This study presents a phase-engineered synthesis of atomically thin α-Te nanosheets and β-Te nanoribbons on WS₂ substrates, achieving high on-state currents and excellent electrical properties. The synthesis is guided by an atomic cluster density and interface-guided multiple control strategy, allowing for the precise control of phase and thickness. As the thickness decreases, α-Te nanosheets transition from metallic to n-type semiconducting properties, while β-Te nanoribbons remain p-type semiconductors with high mobility and on-state current density. Both phases exhibit good air stability after several months. The β-Te nanoribbons show remarkable electrical properties, including an on-state current density of ~1527 μA μm⁻¹ and a mobility of ~690.7 cm² V⁻¹ s⁻¹ at room temperature. Short-channel β-Te nanoribbon transistors exhibit an on-state current density of ~1270 μA μm⁻¹ and an on-state resistance of ~0.63 kΩ μm at V_DS = 1 V. The phase engineering of α-Te and β-Te is crucial for the development of advanced optoelectronic devices, such as memory devices, high-performance transistors, and reconfigurable circuits.This study presents a phase-engineered synthesis of atomically thin α-Te nanosheets and β-Te nanoribbons on WS₂ substrates, achieving high on-state currents and excellent electrical properties. The synthesis is guided by an atomic cluster density and interface-guided multiple control strategy, allowing for the precise control of phase and thickness. As the thickness decreases, α-Te nanosheets transition from metallic to n-type semiconducting properties, while β-Te nanoribbons remain p-type semiconductors with high mobility and on-state current density. Both phases exhibit good air stability after several months. The β-Te nanoribbons show remarkable electrical properties, including an on-state current density of ~1527 μA μm⁻¹ and a mobility of ~690.7 cm² V⁻¹ s⁻¹ at room temperature. Short-channel β-Te nanoribbon transistors exhibit an on-state current density of ~1270 μA μm⁻¹ and an on-state resistance of ~0.63 kΩ μm at V_DS = 1 V. The phase engineering of α-Te and β-Te is crucial for the development of advanced optoelectronic devices, such as memory devices, high-performance transistors, and reconfigurable circuits.