Dramatic switchable polarities in conduction type and self-driven photocurrent of BiI₃ via pressure engineering

Area of Science:

• Materials Science
• Condensed Matter Physics
• Semiconductor Physics

Background:

• Semiconductor technologies rely on controlled carrier characteristics.
• Switchable and reversible control of carrier polarity in a single material is a key challenge for device optimization.

Purpose of the Study:

• To achieve switchable and reversible p-n switching in a single material via pressure-induced phase transition.
• To investigate the impact of pressure on the photoelectric properties of BiI₃.
• To explore the potential of pressure engineering for designing advanced optoelectronic devices.

Main Methods:

• Inducing semiconductor-semiconductor phase transition in BiI₃ using external pressure.
• Monitoring carrier polarity switching via photocurrent measurements dominated by the photothermoelectric (PTE) effect in a zero-bias two-terminal device.
• Characterizing photoelectric properties under varying pressure and external bias.

Main Results:

• Demonstrated dramatic reversible p-n switching in BiI₃ during a pressure-induced phase transition.
• Observed a switch between positive and negative photocurrents, correlating with the p-n transition and providing a method to determine material conduction type.
• Enhanced photoresponse and extended detection bandwidth to 1650 nm due to combined photoconductivity and PTE effects.
• Attributed improved properties to enhanced energy band dispersion and increased charge density under pressure.

Conclusions:

• Pressure engineering offers an effective and flexible method for modulating carrier properties in semiconductors.
• Reversible p-n switching in BiI₃ via pressure provides a pathway for developing multifunctional logic circuits and optoelectronic devices.
• Photoelectric measurements, particularly utilizing the PTE effect, can serve as a tool for determining material conduction types.