PdSe₂/Germanium Nanocones Heterojunction As High-Performance Infrared Light Photodetector

With the rapid development of optoelectronic device,photodetectors,as an important component of sensors,play an important role in military,civil and other fields.In recent years,with the development of semiconductor technology,semiconductor materials are usually etched into nanorods,nanowires,nanocones.The optical absorption of semiconductor materials and the photoelectric conversion efficiency of devices will be improved.This method is commonly applied in solar cells and photodetectors.In this study,we are presenting a sensitive infrared photodetector composed of germanium nanocones?GeNCs?array and PdSe₂ multilayer,which is obtained by a straightforward selenization approach.GeNCs were prepared by the metal assisted chemical etching method,and multilayer films of PdSe₂ were prepared by direct selenization.The as-assembled PdSe₂/GeNCs hybrid heterojunction exhibited obvious photovoltaic behavior to 1550 nm illumination,which renders the IRPD a self-driven device without external power supply.Further device analysis revealed that the PdSe₂/GeNCs hybrid photodetector exhibited high sensitivity to 1350,1550,and 1650 nm illumination with excellent stability and reproducibility.The responsivity and EQE was as high as 530.2 mA/W and 42.4%,respectively.Such a relatively good device performance is related to the strong light trapping effect of GeNCs array,according to our theoretical simulation based on finite-difference time-domain?FDTD?.It is also found that the device showed an abnormal sensitivity to infrared illumination with wavelength of 2200 nm.The rise and fall time of the device were 21.2?s/40.2?s.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.