Cross-sectional Kelvin probe force microscopy on III-V epitaxial multilayer stacks: challenges and perspectives
Mattia da Lisca1,2,3, José Alvarez1,2,3, James P Connolly1,2,3
1Institut Photovoltaïque d'Ile de France, 30 Route Départementale 128, 91120, Palaiseau, France.
Beilstein Journal of Nanotechnology
|June 22, 2023
Summary
Frequency-modulated Kelvin probe force microscopy (KPFM) effectively analyzes multilayer III-V solar cells. This technique maps surface potential, revealing crucial interface mechanisms for enhanced solar cell efficiency.
Area of Science:
- Materials Science
- Nanotechnology
- Renewable Energy
Background:
- Multilayer III-V solar cells are complex devices with critical interfaces.
- Understanding interface mechanisms is key to improving solar cell efficiency.
Purpose of the Study:
- To investigate the capability of frequency-modulated Kelvin probe force microscopy (KPFM) for analyzing InP/GaInAs(P) multilayer stacks.
- To correlate KPFM surface potential measurements with device properties.
Main Methods:
- Utilized frequency-modulated Kelvin probe force microscopy (KPFM) under ambient conditions.
- Analyzed surface potential variations to identify space charge regions and junctions.
- Performed KPFM under illumination to study photogenerated carrier effects.
Main Results:
- KPFM demonstrated strong dependence on local doping concentration, resolving surface potential at the 20 nm scale.
- Identified space charge regions and multiple junctions within the multilayer stack.
- Observed contrast enhancement under illumination, attributed to reduced surface band bending by photogenerated carriers.
Conclusions:
- KPFM is a valuable tool for characterizing multilayer III-V solar cells at the nanoscale.
- The technique provides insights into interface properties and junction behavior.
- Illuminated KPFM offers further understanding of carrier dynamics and defect interactions.
