Physics of Internal Photoemission and Its Infrared Applications in the Low-Energy Limit

Figure 10

The spectral (a) responsivity and (b) detectivity at 80 K. The vertical arrows indicate the occurrence of zero response due to bidirectional photocurrents simultaneously existing in the device, owing to the photovoltaic operating mode. Labeled responses and correspond to the forward [] and reverse [] photocurrents. Long-wavelength response beyond 3.9 m was not observed in flat-barrier sample SP1001. Table 2 summarizes the threshold wavelengths of photovoltaic response for three samples. The value of SP1007 is times higher than 30-period photoconductive detectors previously reported [12].

(a)

(b)