Diffusion length of non-equilibrium minority charge carriers in β-Ga2O3 measured by electron beam induced current
Abstract
The spatial distribution of electron-hole pair generation in β-Ga2O3 as a function of scanning electron microscope (SEM) beam energy has been calculated by a Monte Carlo method. This spatial distribution is then used to obtain the diffusion length of charge carriers in high-quality epitaxial Ga2O3 films from the dependence of the electron beam induced current (EBIC) collection efficiency on the accelerating voltage of a SEM. The experimental results show, contrary to earlier theory, that holes are mobile in β-Ga2O3 and to a large extent determine the diffusion length of charge carriers. Diffusion lengths in the range 350–400 nm are determined for the as-grown Ga2O3, while processes like exposing the samples to proton irradiation essentially halve this value, showing the role of point defects in controlling minority carrier transport. The pitfalls related to using other popular EBIC-based methods assuming a point-like excitation function are demonstrated. Since the point defect type and the concentration in currently available Ga2O3 are dependent on the growth method and the doping concentration, accurate methods of diffusion length determination are critical to obtain quantitative comparisons of material quality.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- May 09, 2018
- Source ID
- 10.1063/1.5027559
Entities
People
- A. Y. Polyakov
- Eugene Yakimov
- Fan Ren
- Gwangseok Yang
- I. V. Shchemerov
- Jiancheng Yang
- Jihyun Kim
- N. B. Smirnov
- Stephen Pearton
Organizations
- Defense Threat Reduction Agency
- Korea Institute of Energy Technology Evaluation and Planning
- Korea University
- Ministry of Education and Science of the Russian Federation
- National University of Science and Technology
- Russian Academy of Sciences
- University of Florida