Polarity modulation in compositionally tunable Bi₂O₂Se thin films

Area of Science:

• Materials Science
• Condensed Matter Physics
• Semiconductor Device Physics

Background:

• Two-dimensional (2D) materials are crucial for beyond-silicon electronics.
• Bismuth oxyselenide (Bi2O2Se) shows promise due to high electron mobility and a native high-k dielectric.
• Fabricating p-type 2D Bi2O2Se transistors is a significant challenge.

Purpose of the Study:

• To develop an area-selective, low-temperature doping method for Bi2O2Se thin films.
• To enable the modulation of carrier polarity in 2D Bi2O2Se.
• To demonstrate the fabrication of p-type Bi2O2Se devices and p-n homojunctions.

Main Methods:

• Utilized pulsed laser deposition for Bi2O2Se thin film fabrication.
• Employed an area-selective doping strategy introducing Zn2+ substitutional dopants at ~600 K.
• Compatible with back-end-of-line processes for integrated circuit manufacturing.

Main Results:

• Achieved area-selective doping of Bi2O2Se thin films at low temperatures.
• Successfully modulated carrier polarity, enabling p-type conductivity.
• Demonstrated a 2D vertical p-n homojunction with a photoresponse on/off ratio of ~10^6.
• Fabricated planar transistors utilizing p-doped Bi2O2Se homojunctions.

Conclusions:

• The developed low-temperature doping method overcomes challenges in p-type Bi2O2Se fabrication.
• This technique facilitates the creation of advanced 2D electronic devices, including p-n homojunctions.
• Promotes the application of Bi2O2Se in next-generation electronic technologies.