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Photo-Scanning Capacitance Microscopy and Spectroscopy Study of Epitaxial GaAsN Layers and GaAsN P-I-N Solar Cell
Adam Szyszka1, Wojciech Dawidowski1, Damian Radziewicz1
1Faculty of Electronics, Photonics and Microsystems, Wrocław University of Science and Technology, Janiszewskiego 11/17, 50-327 Wrocław, Poland.
Nanomaterials (Basel, Switzerland)
|July 25, 2025
Summary
Investigating Gallium Arsenide Nitride (GaAsN) solar cells with light-assisted scanning capacitance microscopy (SCM) reveals nanoscale variations in properties. This advanced SCM technique offers new insights into complex dilute nitride semiconductor structures.
Area of Science:
- Materials Science
- Semiconductor Physics
- Optoelectronics
Background:
- Growing high-quality Gallium Arsenide Nitride (GaAsN) with controlled nitrogen incorporation is challenging, leading to inhomogeneous opto-electrical properties in epitaxial layers.
- Standard characterization methods often fail to identify subtle spatial variations in GaAsN structures.
- Understanding these inhomogeneities is crucial for optimizing GaAsN-based p-i-n solar cell performance.
Purpose of the Study:
- To present a novel light-assisted scanning capacitance microscopy (SCM) and spectroscopy approach for investigating GaAsN layers and solar cell structures.
- To achieve nanoscale resolution for mapping carrier concentration, electric fields, and deep-level transitions.
- To provide spatially resolved insights into complex dilute nitride semiconductor materials.
Main Methods:
- Utilized light-assisted scanning capacitance microscopy (SCM) with localized cross-section measurements.
- Employed wavelength-tunable optical excitation ranging from 800-1600 nm.
- Performed comparative analysis with electrochemical capacitance-voltage (EC-V) profiling and photoluminescence spectroscopy.
Main Results:
- Successfully resolved nanoscale carrier concentration profiles, internal electric fields, and deep-level transitions across GaAsN p-i-n solar cell structures.
- Identified multiple localized transitions attributed to compositional fluctuations and nitrogen-induced defects.
- Revealed spatial variations in energy states, including discrete nitrogen-rich regions and gradual nitrogen content changes, not detectable by standard methods.
Conclusions:
- Light-assisted photo-scanning capacitance microscopy and spectroscopy is a powerful technique for characterizing complex dilute nitride structures.
- The method provides unique, spatially resolved insights into material inhomogeneities affecting opto-electrical properties.
- This technique offers a universal and accessible tool for evaluating semiconductor structures and optoelectronic devices.
