In this study, a sensitive infrared photodetector (IRPD) composed of a
germanium nanocones (GeNCs) array and PdSe2 multilayer is presented, which
is obtained by a straightforward selenization approach. The as-assembled
PdSe2/GeNCs hybrid heterojunction exhibits obvious photovoltaic behavior
to 1550 nm illumination, which renders the IRPD a self-driven device without
external power supply. Further device analysis reveals that the PdSe2/GeNCs
hybrid based IRPD exhibits high sensitivity to 1350, 1550, and 1650 nm
illumination with excellent stability and reproducibility. The responsivity
and external quantum efficiency is as high as 530.2 mA W−1 and 42.4%,
respectively. Such a relatively good device performance is related to the strong
light trapping effect of GeNCs array, according to the theoretical simulation
based on finite-difference time-domain. It is also found that the IRPD shows an
abnormal sensitivity to IR illumination with a wavelength of 2200 nm. Finally,
the present individual IRPD can also record the simple “F” image produced by
1550 nm, suggesting the promising application of the PdSe2/GeNCs hybrid
device in future infrared optoelectronic systems.