Study On Novel Mn-co-ni-o Film Bolometer

Bolometer,which has the characteristics of high response,high integration,and room-temperature detection,has been widely used in infrared fields such as thermal imaging,satellite remote sensing,environmental monitoring,night vision,and material detection.However,the small absorption coefficient of thermal materials such as vanadium oxide and amorphous silicon,the difficulty in the fabrication of �1/4 wavelength�resonator in the microbridge structure,and large background noise have restricted the development and application of bolometer in terahertz and millimeter wave bands.Therefore,the development of high-performance bolometer in terahertz and millimeter wave has become a hot spot in the current research.On the other hand,detectors that integrate multiple detection functions have also been an important development trend with the rapid development of third-generation detection technology.For example,in the fields of biomolecules identification and characteristic spectrum of material detection,detectors should process the ability of narrowband detection;however,the bolometer is a kind of wide-spectrum response device insensitive to the wavelength of incident light.In terms of material and tissue characteristics,surface roughness of objects,and high-contrast detection in complex environments,the detector should be polarization-sensitive.Unfortunately,most of the current polarization-detection devices rely on a separate polarizer,resulting in large volumes,complex structures and relatively high costs.If the functions of narrowband,polarization sensitive and angle selection can be integrated in bolometer,it will greatly benefit to the application in these fields.Recently,a transition metal oxide Mn-Co-Ni-O thermal material with advantages of large negative temperature coefficient,wide spectral responsivity,low fabrication cost and stable performance has gradually become a research hot spot.It is also expected to become an excellent material for the next generation of bolometer through optimizing the optical and electrical properties of Mn-Co-Ni-O thermal material.In different components of Mn-Co-Ni-O films,the Mn_1.56Co_0.96Ni_0.48O₄(MCNO)film has a high absorption coefficient in the long-wave infrared band(8-14?m) and far-infrared band(14-30?m).At present,the MCNO film bolometer has been widely used in earth radiation monitoring,infrared imaging and many other fields.However,the weak absorption of MCNO films seriously hinders their applications in the mid-infrared (3-6?m),where the extinction coefficient is a very small value.The main content and innovations of the paper are as follows:In the first part,we design and fabricate an enhanced infrared detector based on silicon dielectric structures.By introducing a silicon dielectric structure layer on the surface of the sensitive element as a guide layer for coupling a specific wavelength of electromagnetic waves into MCNO films,the energy of the incident light is localized inside the MCNO film in order to enhance the absorption of the MCNO film in the device,thereby increasing the responsivity of the detector.Compared with coating black paint absorption layer on the surface of the sensitive element,this method is more environmentally friendly and more suitable for array detectors,which avoids the uneven coating of the black paint absorption layer on different pixels.Compared with the metal artificial metasurface based on the plasmon,this method can avoid energy dissipation of the metal material in infrared band,thereby increasing the absorption of MCNO films.After introducing a silicon dielectric structure layer on the surface of the MCNO film,the responsivity of the device was increased from 1.31 V/W to 1.85V/W,with an increase rate of 41.22%.The room temperature detectivity D*of the device with silicon structure layer under 500 K blackbody radiation can reach2.53�10⁶cm�Hz^1/2�W^-1.In the second part,we design and fabricate a high-performance and polarization-sensitive MCNO terahertz detector with a �11�6� rectangular metal hole array.The measured room-temperature responsivity of the traditional MCNO thin-film detector is 0.52 V/W at 300 GHz with a modulation frequency of 10 Hz,while the responsivity of the MCNO thin-film detector with the absorption structure reaches 2.27 V/W,which increased by 336.53%.And the detectivity D*of device can reach up to 2.19�10⁶cm�Hz^1/2�W^-1.In addition,our device is also capable of narrowband detection.The absorption of the MCNO film can reach up to 55%,and the quality factor (Q value)of the absorption spectrum can reach 13.64.At the same time,our device has the polarization detection capability,and the extinction ratio can reach up to 8.44.Our approach is simple,compatible with integrated circuit technology,and can be applied to improve the performance of microwave and THz MCNO array detectors,narrowband detection and polarization detection in the future.Moreover,this method is also applicable to other types of thermal detectors.In the third part,we design and fabricate a high-performance and polarization-sensitive MCNO millimeter-wave bolometer based on the antenna effects,and successfully introduce a periodic grating structure on the sensitive element to further improve the response of the device.The measured room-temperature responsivity is about 440.2 V/W,NEP is 1.3�10^-9W�Hz^-1/2and detectivity is 6.7�10⁶cm�Hz^1/2�W^-1at 28GHz with the modulation of 10 Hz.In addition,our device achieves sensitive polarization detection with polarization extinction ratio of more than 24.The new proposed device is simple,effective,compatible with current manufacturing process,and can be applied to improve the performance of MCNO array detectors.