Fig. 1. (a) Schematic for the Ge:P BIB detectors. (b) Partly false-color SEM image for a unit of the detectors; inset: two magnified interdigital cells. (c) The density profile of P atoms in the AL, which was obtained by SIMS measurement.

Fig. 2. Schematic of the measurement setup for response spectra.

Fig. 3. Response spectra of detectors (a) #1 and (b) #2 at different biases and 4.5 K. (c) and (d) Peak intensities of the two bands and their ratio versus bias for the spectra in (a) and (b), respectively, where Rp represents the peak intensity, Rp(IR)/Rp(THz) represents the ratio of IR peak intensity to THz one. (e) Peak intensities of the tiny MIR band versus bias of the two detectors. (f) Energy band diagram for the Ge:P BIB detectors to reveal the origin of the ultra-broadband multiband IR/THz response, where CB and VB represent conduction and valence bands respectively, D+ and A− represent ionized donors and ionized acceptors before IR/THz irradiation respectively, and solid and hollow spheres represent photo-generated electrons and holes respectively.

Fig. 4. (a) Response spectra of detector #3 at different biases and 4.5 K, where the THz response band is left out for all of the spectra with above-150 mV biases since the intensity of this band already saturates; inset: magnified spectra within 3–4.2 μm for all biases. (b) Peak intensity of the IR band versus bias for the spectra in (a). (c) Response spectra at different temperatures and 400 mV of detector #3. (d) Peak intensity of the IR band versus temperature for the spectra in (c).

Fig. 5. Schematic of the measurement setup for blackbody responses.

Fig. 6. (a) Relative response spectrum of detector #1 measured at 4.5 K and 150 mV, where the HDPE window was used as a low-pass filter. (b)–(d) Blackbody responsivities versus bias at different temperatures for the three detectors, respectively. (e) Dark I-V characteristics for the three detectors at 4.5 K.