Capacitive β-Ga2O3 solar-blind photodetector with graphene electrode

Conventional solar-blind photodetectors based on the conduction of photoexcited carriers are energy inefficient owing to the power dissipation caused by a resistive sensing mechanism and the narrow bandgap energy of the photon-absorbing layer. Herein, we demonstrate the energy-efficient capacitive sensing of deep-UV wavelengths by integrating an intrinsically solar-blind ultrawide bandgap (UWBG) β-Ga2O3 semiconductor with UV-transparent and conductive graphene electrode. A UWBG β-Ga2O3 eliminates the requirement of a solar-blind deep-UV bandpass filter. The high optical transmittance of the graphene enables UV-C light to be absorbed in the underlying β-Ga2O3, thereby facilitating carrier transport between the graphene electrode and β-Ga2O3. A capacitance change under UV-C excitation is observed, along with excellent reproductivity and spectral selectivity at various frequencies and bias …