Study On Responsivity Optimization Of HgTe Quantum Dots Photodetector

The design of an integrated focal plane array and silicon readout circuit can use conventional infrared photodetector materials,but the integration process’complexity raises the price of photodetector preparation.Many new photodetector materials,including quantum dots,nanowires,and new two-dimensional materials,have emerged in recent years with the growth of micro and nanotechnology.Due to their distinct properties of size effect,quantum limiting effect,and liquid phase production,quantum dot materials are one of the most promising materials for high performance and low cost photodetectors.Compared with other quantum dots,HgTe quantum dots have a wider spectral response range,which can satisfy the detection range from visible light to mid-wave infrared.Therefore,in this paper,the quantum dot layer and device structure were optimized based on HgTe quantum dots prepared by hot injection method,and the silicon based HgTe quantum dot photodetector was prepared,which not only broadened the response range of the silicon based detector,but also enabled it to be applied in the field of integrated circuits and optoelectronics.This paper’s research findings are as follows:（1）Investigate the synthesis of HgTe quantum dots.Thermal injection was used to create HgTe quantum dots with mercury chloride（Hg Cl₂）as the mercury source and TOPTe as the tellurium source.The reaction temperature was adjusted during the synthesis process to see how it affected the particle size of the quantum dots,and then the particle size was statistically increased from 5.5 nm to 12.7 nm.The synthesis temperature in this paper is 80℃,the synthesis time is 3 min,the particle size is about 9.1 nm,and the absorption peak is about 2300nm HgTe quantum dots.The quantum dots synthesized under this parameter have good dispersion and can meet the required wavelength requirements.（2）Make the quantum dot layer better.The long chain ligand is replaced with the short chain ligand using various ligand exchange reagents to manufacture the photoconductive device,increasing the carrier mobility and responsiveness of the device.The detector’s response is 6.8m A/W at a wavelength of 980 nm.The second strategy involves improving the ligand exchange approach.After the coating is complete,the device is submerged in the cleaning agent for a predetermined amount of time to increase the ligand exchange and device performance.The responsiveness is 8.1 m A/W at a wavelength of 980 nm.（3）Improve the device structure.A silicon-based HgTe quantum dot infrared photodiode detector was built in this paper,and the effects of five different types of silicon with varying electrical resistivity on device performance were investigated.With a wavelength of 980 nm and a power of 30 m W,It was found that the device prepared on a silicon substrate with a synthesis temperature of 80℃and a resistivity of 20-50 ohm.cm had the best performance parameters.When the bias is set to 1 V,the measured device’s responsiveness is 40 m A/W.At a wavelength of 1550 nm,the device’s responsivity is 0.2 m A/W.This research points the way forward for the advancement of silicon technology in the future.