High-speed Photoelectric Detection Of Low Dimensional Materials

Low dimensional materials refer to materials which are small enough in size（<100nm）in at least one dimension.Compared to traditional bulk materials,the optoelectronic response of low dimensional materials has advantages such as high polarization sensitivity,fast photoresponse speed,and wide detection wavelength.Therefore,they have broad application prospects in the field of optoelectronic detection and deserve in-depth research.When testing the optoelectronic performance of low dimensional materials,selecting a suitable amplifier can help us obtain a more accurate test of the material’s optical response speed.Therefore,this article explores the direct use of current amplifiers to test the optoelectronic performance of two-dimensional materials,including commercial amplifiers（SR570,DLPCA-200）and cross resistance amplifier modules based on AD825.Through comparison,AD825 high-speed JFET amplifiers with fast response speed and good noise indicators were selected,and their important performance indicators were simulated and tested,and multiple low-temperature systems were subsequently selected for optoelectronic performance testing.This article tested the photoelectric performance of（NbSe₄）₃I and found that（NbSe₄）₃I has conductivity at a temperature of 50 K.Subsequently,the AD825amplifier was used to test the response speed of（NbSe₄）₃I and it was found that（NbSe₄）₃I has a fast light response speed and stability,with a response speed of less than 0.1milliseconds.The conductivity characteristics of（NbSe₄）₃I at low temperatures are influenced by both light excitation and temperature,but when the temperature is above90 K,the effect of laser excitation on the conductivity characteristics is relatively weak.Moreover,the photocurrent response and Raman spectra of the（NbSe₄）₃I sample exhibit significant anisotropy.However,the test results indicate that（NbSe₄）₃I only exhibits light response characteristics at low temperatures,with limited usage environments.Black phosphorus has received widespread attention due to its unique anisotropy and tunable bandgap.In order to explore better photoelectric detection materials,we subsequently tested the photoelectric performance of thin layer black phosphorus.we tested the photoelectric performance of thin layer black phosphorus.It was found that black phosphorus has a low dark current at room temperature,and has photoresponse at wavelengths of 450 nm,520 nm,638 nm,and 808 nm,with a response speed of 0.2milliseconds.The noises from black phosphorus at room temperature are also measured respectively.It is demonstrated that the frequency-dependent 1/f noise accounts for the main part of the total noise of black phosphorus under different conditions.Finally,we found that the formation of BP/In₂Se₃ heterojunction can improve the response speed of the sample.