Mapping the Energy Landscape from a Nanocrystal-Based Field Effect Transistor under Operation Using Nanobeam...

Area of Science:

• Nanocrystal optoelectronics
• Advanced materials characterization

Background:

• Maturing field of nanocrystal (NC)-based optoelectronics requires advanced characterization techniques.
• Current methods like optical spectroscopy and electrochemistry often lack device-relevant conditions or absolute energy references.
• Probing NCs within their operational environment (e.g., with transport layers, electrodes, and applied fields) is crucial for device optimization.

Purpose of the Study:

• To explore photoemission microscopy as a strategy for *operando* (in-operation) investigation of NC-based devices.
• To demonstrate the applicability of photoemission microscopy across diverse NC materials and device architectures.
• To showcase the method's capability in directly accessing critical electronic properties at interfaces.

Main Methods:

• Utilized photoemission microscopy for *operando* analysis of nanocrystal devices.
• Applied the technique to various NC materials and device geometries.
• Investigated electronic structure under applied electric fields and within device environments.

Main Results:

• Demonstrated the versatility of photoemission microscopy for different NC materials and device configurations.
• Provided direct access to metal-semiconductor interface band bending.
• Quantified the propagation distance of the gate effect in field-effect transistors.

Conclusions:

• Photoemission microscopy is a powerful tool for *operando* characterization of NC-based optoelectronic devices.
• The technique enables detailed understanding of electronic structure and interfacial phenomena crucial for device performance.
• This method facilitates direct probing of band bending and gate modulation effects, aiding in device optimization.