Fig. 1. (a) QCSE in a single quantum well. (b) Energy band diagram of AlGaN SBUV p-i-n photodiode with MQW in the intrinsic depletion region.

Fig. 2. Photodiode structures (a) with and (b) without MQW.

Fig. 3. (a) Simulated I-V curves in dark and on illumination for devices SA and SB. (b) Simulated spectral responses for devices SA and SB at 5 V bias.

Fig. 4. Simulated energy bands for devices (a) SA and (b) SB, (c) electron and (d) hole current densities, (e) electron and (f) hole concentrations in dark and on illumination at 5 V bias, respectively.

Fig. 5. (a) Schematic structure diagram of device SA. (b) Cross-sectional STEM image of device SA. (c) Enlarged STEM image for the MQW region in device SA. (d) Plane-view OM image of the fabricated devices.

Fig. 6. (a) Photo and dark currents for devices SA and SB. (b) Spectral responses of device SA at zero bias. Inset is the log-scale plot. (c) Bias-dependence of peak responsivity and EQE of device SA. (d) Zero-bias peak responsivity and wavelength of device SA and some reported AlGaN self-powered SBUV detectors [14,15,25,30,34,41–63" target="_self" style="display: inline;">–63].