Fig. 1. Proposed design for the impulse response analysis of the GST-based PD device.

Fig. 2. For the 150 nm thick cGST on 220 nm thick Si at the time of illumination: (a) potential distribution at 4 V, 2 V, and 0.5 V biasing, (b) electric field distribution for 2 V biasing.

Fig. 3. Carrier current (Jc), displacement current (Jd), and total current (J0) for a 150 nm thick cGST biased at 2 V illuminated at 1550 nm. The current component’s behavior is shown in the inset.

Fig. 4. J0 for different thicknesses of cGST biased at 2 V for 1550 nm wavelength illumination with the responsivity of both phases of GST at different thicknesses under similar illumination and biasing conditions. The variation in responsivity with thickness at 1550 nm is shown in the inset.

Fig. 5. Total current (J0) for the 150 nm thick aGST and cGST biased at 2 V illuminated at 1550 nm.

Fig. 6. Impulse response of device illuminated at wavelengths of 1150 nm, 1550 nm, and 1850 nm for a 2 V biased 150 nm thick (a) cGST and (b) aGST.