Size-Dependent Isovalent Impurity Doping for Ambipolar Control in Cu₃N.

Area of Science:

• Materials Science
• Solid State Physics
• Semiconductor Physics

Background:

• Substitutional doping with aliovalent impurities is key for semiconductor ambipolar control.
• Monovalent cation compounds face limitations in p-type doping due to a lack of suitable aliovalent impurities.

Purpose of the Study:

• To explore an alternative doping strategy for Cu(I)-based semiconductors using isovalent alkali metal impurities.
• To achieve controllable p-type and n-type doping in copper nitride via impurity size manipulation.

Main Methods:

• Investigated doping effects of isovalent lithium (Li), cesium (Cs), and rubidium (Rb) in copper nitride.
• Utilized first-principles calculations to understand impurity behavior and defect formation.
• Controlled electron and hole concentrations through impurity size variations.

Main Results:

• Smaller Li impurities at interstitial positions enhanced n-type conductivity (10^15 to 10^18 cm^-3).
• Larger Cs and Rb impurities induced p-type conversion (10^14 to 10^17 cm^-3) by forming acceptor defect complexes.
• Li acts as a shallow donor, while Cs/Rb promote Cu vacancies due to ionic repulsion.

Conclusions:

• Isovalent impurity size-dependent doping offers a new route for semiconductor doping.
• This method provides tunable n-type and p-type conductivity in monovalent cation compounds.
• Enables advancements in optoelectronic devices utilizing copper nitride and similar semiconductors.