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Updated: Aug 30, 2025
All-electronic Nanosecond-resolved Scanning Tunneling Microscopy: Facilitating the Investigation of Single Dopant Charge Dynamics
Published on: January 19, 2018
Contactless doping characterization of [Formula: see text] using acceptor Cd probes
Marcelo B Barbosa1,2, João Guilherme Correia3,4, Katharina Lorenz5
1IFIMUP, Institute of Physics for Advanced Materials, Nanotechnology and Photonics, Departamento de Física e Astronomia da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, 4169-007, Porto, Portugal. marcelo.barbosa@fc.up.pt.
This study demonstrates Cadmium (Cd) as a p-type dopant in Gallium Nitride (GaN) using ion implantation and nuclear transmutation. This breakthrough enables advanced characterization and contactless mobility studies for next-generation power electronics.
Area of Science:
- Materials Science
- Solid State Physics
- Semiconductor Research
Background:
- Wide bandgap semiconductors like Gallium Nitride (GaN) are crucial for next-generation power electronics.
- Developing reliable p-type doping and characterization methods for GaN is essential for advancing device performance.
Purpose of the Study:
- To investigate Cadmium (Cd) as a potential p-type dopant in GaN.
- To establish robust doping and characterization techniques for Cd-doped GaN.
- To explore contactless methods for assessing charge carrier properties.
Main Methods:
- Ion implantation, diffusion, and nuclear transmutation were used for Cd incorporation into GaN.
- Perturbed Angular Correlation (PAC) spectroscopy was employed for atomic-scale characterization.
- Density Functional Theory (DFT) simulations were utilized to understand doping mechanisms.
Main Results:
- The acceptor character of Cd in GaN was confirmed, with Cd occupying the octahedral Ga site in a negative charge state.
- No significant polaron deformations or nearby point defects were observed around the Cd dopants.
- Contactless charge mobility studies revealed thermally activated free electrons above 648 K and tunneling-dominated transport at lower temperatures.
Conclusions:
- Cd doping in GaN is a viable route for achieving p-type conductivity.
- PAC and DFT provide powerful tools for characterizing dopant behavior and charge states without ohmic contacts.
- The findings pave the way for contactless characterization of charge mobility in wide bandgap semiconductors.
