Exfoliated and bulk β-gallium oxide electronic and photonic devices

Abstract

<h2>Abstract</h2> Monoclinic gallium oxide (β-Ga₂O₃) has recently attracted increasing attention due to the availability of high quality, large diameter single crystals from mature melt growth methods and its attractive material properties of wide E_G of 4.6–4.9 eV, good electron mobility (>200 cm²/Vs) and estimated E_c of ~8 MV/cm. Compared to other ultra-wide bandgap materials, the inexpensive substrates lower the manufacturing cost for β-Ga₂O₃ power devices. Applications of deep-UV detectors with solar blindness include inspection of high voltage transmission lines for corona and partial discharges, detection of fires and various defense systems. Si- and GaAs-based UV PDs are not truly solar-blind, as additional, bulky visible-light blocking filters are required. In this short review we discuss the use of bulk and exfoliated β-Ga₂O₃ for these applications and relate this to the basic surface and response of the material to high temperatures, radiation exposure and typical semiconductor processing steps. The material can easily be cleaved along the (100) surface and layers with (100)A surface termination have higher energy than the (100)B termination. The (100)B cleavage plane is the favorable one, observed experimentally.