Evaluation of Fe-βGa2O3for Photoconductive Semiconductor Switching
Karen M. Dowling (Lawrence Livermore National Laboratory, TU Delft - Beijing Delft Institute of Intelligent Science and Technology, TU Delft - Electronic Instrumentation)
Bikramjit Chatterjee (Lawrence Livermore National Laboratory)
Soroush Ghandiparsi (Lawrence Livermore National Laboratory)
Qinghui Shao (Lawrence Livermore National Laboratory)
Joel Varley (Lawrence Livermore National Laboratory)
Joseph D. Schneider
Caitlin Chapin (Lawrence Livermore National Laboratory)
Miranda S. Gottlieb
Laura Leos (Lawrence Livermore National Laboratory)
Michael Sword (Lawrence Livermore National Laboratory)
Sara Harrison (Lawrence Livermore National Laboratory)
Lars Voss (Lawrence Livermore National Laboratory)
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Abstract
We present iron-doped beta gallium oxide (Fe-ßGa2O3) as a candidate for photoconductive semiconductor switches (PCSSs) with sub-bandgap light. From a commercially available Fe-ßGa2O3 wafer, we first did material characterization. This included measurements of absorption coefficient and dopant composition, carrier activation energy up to 200 C, break down field of planar electrodes (limited from material passivation), and free carrier recombination lifetime, and thermal effects up to 203 C on photocurrent with a 447 nm light emitting diode (LED) source. We then demonstrated pulsed operation of a Fe-ßGa2O3 PCSS under different sub-bandgap wavelengths (355, 532, and 1064 nm) and sub-ns pulses. Fe-ßGa2O3 is a candidate for high temperature PCSS with 355 nm responsivity of 7 × 10-7 A-cm/W-kV at room temperature and up to 5.5 × 10-4 A-cm/W-kV at 200 C. From these investigations, we discuss a simple trap model to describe the illumination process of the PCSS. Fe-ßGa2O3 has a high breakdown field and has moderate responsivity characteristics, but the dark current at high temperature leads to low photo-to-dark current ratio (PDCR). Regardless, we verify its potential as a PCSS material for harsh environment applications.