The Application Of Micro-nano Materials In Infrared And Strain Sensors

Nowadays,infrared detector and strain sensor play important roles in industrial production and daily life,and many researchers have made great efforts to improve the performance of them.In this work,we prepared nano materials,construted infrared detector and strain sensor,and then studided their performance.The main works in our rearsch were listed as follows:(1)A type of metal-semiconductor-metal(MSM)photodetector based on PbTe single-crystalline nanowires was prepared.The influences of light intensity,bias voltage,and temperature on the performance of PbTe nanowire photodetector were investigated.The study shows that little dark current was achieved in MSM PbTe nanowire photodetector at low bias voltages due to the formation of back to back Schottky junctions between the PbTe nanowires and Au electrodes.Moreover,this photodetector displayed a fast respond compared with nanoparticle photodetector due to the one dimensional structure and the high crystallinity of nanowires.(2)Infrared detectors with ohmic contact based on PbTe nanowires and PbTe branched structure with different morphologies were constructed,and their performance were studied.It was found that the detector based on PbTe film with dendritic branched structure have the highest responsivity(0.46 AW-1)and detectivity(3.5×109 cm·Hz1/2·W-1).The responsivity was about two orders magtitude and detectivity was about one order magtitude higher than infrared detectors based on PbTe nanowires with ohmic contact.(3)A new type of capacitor-like infrared detector was constructed and its working mechanism was explained.In addition,a new kind of material for infrared detection was explored.Bi nanowires with diameter of 30?40 nm would change into semiconductor with a small bandgap at 77 K,and the bandgap can be changed by adjusting the diameter,which could be used to detect infrared light with different wavelengths.(4)A high strain sensor composed of elastomer polydimethylsiloxane(PDMS)and polyaniline(PANI)was fabricated by electrodeposition method for PAN I preparation and daubing method for PDMS preparation.This kind of sensor could subject to a large tensile strain(-50%)and revealed a high gauge factor(54 at 50%strain),which was higher than other sensors reported previously.Also,the sensor displayed a current with a magnitude of mA when applied to 1V,indicating it didn't need expensive and huge test equipment.Such high gauge factor of the sensor was attributed to two factors,the deformation of PANI film and the effect of cracks.The flexible sensor was proved to be useful in sensing strains and other various applications.