Heterojunction Devices Fabricated from Sprayed n-Type Ga₂O₃, Combined with Sputtered p-Type NiO and Cu₂O

Area of Science:

• Materials Science
• Semiconductor Physics
• Nanotechnology

Background:

• Gallium oxide (Ga2O3) is a promising n-type semiconductor for electronic devices.
• Heterojunctions are crucial for advanced device functionalities, including solar cells and optoelectronics.
• Understanding band alignment and interface properties is key to optimizing heterojunction performance.

Purpose of the Study:

• To investigate the properties of n-type Ga2O3 combined with p-type NiO and Cu2O.
• To evaluate the performance of Ga2O3/NiO and Ga2O3/Cu2O heterojunctions for optoelectronic applications.
• To analyze the band alignment and interface characteristics influencing device performance.

Main Methods:

• Deposition of n-type Ga2O3 via ultrasonic spray pyrolysis at high temperatures.
• Deposition of p-type NiO and Cu2O using radio frequency and reactive, direct-current magnetron sputtering.
• Fabrication and characterization of heterojunctions on indium tin oxide (ITO)-coated glass.

Main Results:

• High rectification observed in fabricated Ga2O3/Cu2O and Ga2O3/NiO heterojunctions.
• Ga2O3/Cu2O exhibited an open-circuit voltage of 940 mV, and Ga2O3/NiO showed 220 mV under simulated solar illumination.
• Favorable band alignment with small conduction band offset for Ga2O3/Cu2O, and large offsets for Ga2O3/NiO were identified.

Conclusions:

• The study demonstrates the potential of Ga2O3-based heterojunctions for solar cells and optoelectronics.
• The Ga2O3/Cu2O heterojunction shows promising performance due to favorable band alignment.
• The interface between Ga2O3 and ITO does not hinder electron transport, enabling novel device designs.