A 7-eV bandgap semiconductor based on silicon-doped α-(AlxGa1−x)2O3 - Nature

A 7-eV bandgap pins Al-Ga-O squarely in the ultra-wide bandgap sweet spot—above diamond, below pure Al2O3. The real variable is not the number; it is silicon doping unlocking n-type conduction, which breaks a decade-long device-engineering deadlock in the Al-Ga-O system. Technical cascade: upstream, MOCVD and MBE epitaxy gain a new Al-Ga-O substrate and target production line; downstream, breakdown fields exceeding 10 MV/cm point to three application vectors—10-kV-class power switches, deep-UV sub-178-nm optoelectronics, and radiation-hardened detectors. Supply-chain exposure: gallium precursors are dual-use items. China's 2023 gallium export restrictions have already created global supply asymmetry, and US BIS controls are likely to extend into UWBG material processing, disrupting order-mix at AIXTRON and AMEC. Competitive positioning: Wolfspeed, Infineon, and Resonac are all staking claims in UWBG. A Nature-level validation will accelerate corporate R&D budgets, but pilot fabs remain two to three years out. Twelve-to-twenty-four-month tail: dense patent filings, first device demonstrations, and a cost-sensitive window where this material class displaces diamond in niche applications.