Fig. 1. Doping interfaces. (a) Doping interface of UTC-PD and MUTC-PD; (b) doping interface of NB-MUTC-PD

Fig. 2. 3 dB bandwidths of three devices at reverse bias voltage of 2 V and incident light intensity of 1×10⁴ W/cm²

Fig. 3. Physical properties of three devices under reverse bias voltage of 2 V. (a) Band structure; (b) internal electric field intensity

Fig. 4. Internal electric field intensity at different reverse bias voltages. (a) MUTC-PD; (b) NB-MUTC-PD

Fig. 5. 3 dB bandwidths of NB-MUTC-PD and MUTC-PD at different reverse bias voltages (incident light intensity is 1×10⁴ W/cm²)

Fig. 6. 3 dB bandwidth of NB-MUTC-PD at different incident light intensities

Fig. 7. Effect of light intensity on properties of NB-MUTC-PD. (a) Electron concentration; (b) energy band; (c) internal electric field intensity

Fig. 8. Effect of voltage on properties of NB-MUTC-PD under high lighting condition. (a) Electron concentration distribution; (b) energy band structure; (c) electric field distribution

Fig. 9. Variation of DC photocurrent density of NB-MUTC-PD and MUTC-PD under different reverse bias voltages with light intensity