Bipolar Semiconducting Properties in α-SnWO₄ Based on the Characteristic Defect Structure

Area of Science:

• Materials Science
• Solid State Physics
• Semiconductor Technology

Background:

• Current information technologies heavily rely on p- and n-type semiconductors.
• Oxide semiconductors offer attractive properties like transparency and high dopability but typically lack bipolar conductivity.
• The absence of p-type semiconducting behavior in oxides is a significant barrier to developing practical devices.

Purpose of the Study:

• To demonstrate bipolar semiconducting properties in oxide materials.
• To investigate the mechanisms behind p-type conductivity in oxides.
• To explore strategies for controlling carrier type in oxide semiconductors.

Main Methods:

• Thermal treatment of α-SnWO₄ within a 100 °C temperature window.
• Comprehensive spectroscopic observations.
• Analysis of defect structures and carrier generation mechanisms.

Main Results:

• Bipolar semiconducting properties were successfully demonstrated in α-SnWO₄.
• A higher concentration of Sn⁴⁺ was observed in p-type α-SnWO₄, suggesting its role in hole-carrier generation via substitutional defects on W⁶⁺ sites.
• Oxygen vacancies were found to migrate, correlating with the transition from p-type to n-type semiconducting behavior.

Conclusions:

• The study demonstrates a viable route to achieving p-type conductivity in oxide semiconductors.
• Sn⁴⁺ substitutional defects on W⁶⁺ sites are crucial for hole-carrier generation in α-SnWO₄.
• Controlling oxygen vacancy migration within octahedral structures offers a strategy for tuning carrier type in oxide semiconductors.