Fig. 1. (a) C-V measured at room temperature with the fitting. The device size is 400  μm×400  μm. (b) Simulated electric field distribution at different bias voltages. (c) Simulated avalanche gain with respect to the reverse bias voltage.

Fig. 2. (a) Dark current curves of a device with a mesa area of 400  μm×400  μm for the temperature range from 77 to 300 K. (b) Measured dark current together with the band-to-band tunneling current and the simulated dark current for the bias voltage between 10.5 and 18 V.

Fig. 3. (a) Arrhenius plot of the dark current for the temperature range between 77 and 275 K. (b) Activation energy versus the forward bias voltage. (c) Dependence of the (1/R0A)−1 on the (p/A)−1 for different mesa sizes at room temperature.

Fig. 4. Measured responsivity under different bias voltages at room temperature. The responsivity of the reference device is also shown.

Fig. 5. Avalanche gain with respect to the reverse bias voltage. The inset is the responsivity with respect to the reverse bias voltage for different wavelengths.

Fig. 6. (a) Measured NEP of the device with respect to wavelength at different reverse bias voltages with the inset showing the measured noise current. (b) The corresponding D⋆ with respect to wavelength. The device size is 400  μm×400  μm.