Energy Band Diagram and Current Transport Mechanism In p-MgO/n-Ga<sub>4</sub>Se<sub>3</sub>S

A p-n heterojunction made of MgO and Ga ₄ Se ₃ S single crystal has been successfully produced. The current- voltage curve analysis has shown that the current conduction mechanism is mostly governed by the Richardson-Schottky mechanism. The width of the effective interface region of the p-n junction was found to be 3.72 × 10 ^-5 cm. The work function and the electron affinity of the Ga ₄ Se ₃ S crystals were also determined as 4.32 and 3.96 eV, respectively. On the other hand, the capacitance-voltage curve analysis, which was carried out in the power range that extends from Bluetooth to WLAN power outputs, reflected a built-in voltage of 0.48 eV and density of noncompensated carriers of 8.2 × 10 ¹⁶ cm ^-3 . The device is observed to exhibit a wide range of negative resistance associated with the tunneling of charged particles at reverse biasing down to ~1.28 V. At that voltage, when exposed to a He-Ne laser beam of ~3 mW, the device reflected a responsivity of ~80. The charge storability increased and the I-V characteristics are significantly shifted. These properties are promising because it indicates the applicability of these tunneling devices in optoelectronics.