Research Of High-performance Narrowband Near Infrared Detector Regular Hexagonal Based Silicon Micro-holes

In recent years,with the increasing detection requirements in optical communications,industrial control,artificial intelligence and other fields,near-infrared photoelectric detection has also become the focus of attention.At this stage,due to the high cost of the filter device and the high difficulty of the integration process,the near-infrared narrowband photodetector is subject to many restrictions in the actual design and preparation process.Silicon-based photodetectors are ideal for integrated optoelectronic devices due to their very good compatibility with CMOS.A high-performance easy-to-integrate silicon-based narrow-band near-infrared photodetector will be constructed in this dissertation.And then,the optimization of simulation design,fabrication process,optoelectrical properties and application on heart-rate measurement are systematically studied.The silicon micro-holes array/graphene Schottky junction photodiode is selected as the research object to investigate the influence between the near-infrared response characteristics and silicon trapping micro-holes structure.Furthermore,this NIR photodetector was then explored in practical application in pulse monitoring.The main research contents and results are as follows:(1)Based on the theory of semiconductor physics and the proven merits of well-developed silicon etching technologies,a regular hexagonal silicon micro-holes array was chosen to improve the optoelectrical properties.Silvaco TCAD,an electronic design automation software,was firstly used to design the three dimensional model of the Schottky diode(SD)based on this regular hexagonal silicon micro-holes array.The optimization of the SD NIR response will be then realized based on investigating the influence between distribution of light field and photo-generated carriers collection and silicon trapping structures.(2)Based on the simulated optimization parameters abovementioned,the regular hexagonal silicon micro-holes array was successfully fabricated,which allows the combination of our experimental conditions and process methods,such as the photolithography and devolopment and the inductively coupled plasma(ICP)etching method.After that,the silicon micro-holes array(Si MHs)/graphene(Gr)SD photodiodes were constructed by transferring the graphene to the silicon bottom as the Schottky contact electrode.Especially,the as-fabricated Si MHs/Gr SD shows an excellent narrow-band NIR response,with a response peak around 1064 nm,a current on-off ratio reaching to as high as 10~7,and the responsivity under-1 V bias voltage reaches 1.03 A/W.The device performance for 1064 nm light of the device is much better than that of planar Si/Gr SD,Si/Gr SD arranged on the top of the substrate and some commercial silicon-based photodetectors.(3)Based on the principle of PPG pulse monitoring,a heart-measurement system was built,which was composed of a regular hexagonal Si MHs/Gr narrow-band NIR photodetector,light-emitting diode and amplifier circuit.The obtained heart-ratio is is comparable to the application of commercial devices in pulse detection.The results pave a way for the design of the silicon micro-holes light trapping structures and construction of NIR photodetectors.