Performance Study On The Production Of PbSe Fused Quantum Dots And Related Detectors

Due to the low-dimensional and nanoscale characteristics of quantum dots（QDs）,they can be grown and processed through low-temperature solvents.With the advantages of low cost,adjustable size,broad spectral response,and strong photostability,QDs have been widely used in optoelectronic applications such as light-emitting diodes,solar cells,and photodetectors.Therefore,QDs are considered one of the most important components in the upcoming wave of semiconductor optoelectronic devices.Lead selenide（PbSe）quantum dots are extremely unstable in air,and the applications were limitted in optical technology.However,because of stronger multiexciton effects,higher photosensitivity,and stronger near-infrared radiation ability than lead sulfide quantum dots,it has been widely used in solar cells and other optical detection devices and attracting widespread attention from scientists.There are many problems in Existing PbSe quantum dot detectors such as narrow detection wavelength range and low responsivity.In this paper,PbSe fused quantum dots were prepared using the annealing effect and the thermal injection method,and were used to develop high-performance optoelectronic devices and field-effect transistor devices.First of all,PbSe quantum dots were prepared using the thermal injection method.The mechanism of the effect of growth temperature on the size of quantum dots are analyzed.By changing the growth temperature of the quantum dots,quantum dots with different particle sizes were prepared.Under different growth temperature conditions,the spectral absorption wavelength of the prepared quantum dots can reach to 2500nm,which are provided important technical support for the development of broad-spectrum detectors.By controlling the growth temperature of the quantum dots,the size and optical properties of the quantum dots can be effectively adjusted.In addition,performance characterization and analysis of quantum dots with different sizes revealed that as the size of the quantum dots increases,their optical properties are also changed accordingly.The larger the quantum size,the worse its singularity.Through these studies,a better understanding of the growth mechanism and optical properties of quantum dots can be achieved.Subsequently,based on the synthesized PbSe quantum dots,a high-quality PbSe quantum dot film with small surface roughness and adjustable thickness was successfully prepared using spin-coating technology and by controlling the baking temperature of the film.Through annealing,a new type of nanomaterial-fused quantum dots-were successfully obtained.The annealing reaction time and temperature were optimized to effectively reduce defects and improve the activity of the fused quantum dots.The fused quantum dots were prepared using the RTP-500 rapid annealing furnace under vacuum and nitrogen filling.The fusionphenomenon of lead selenide quantum dots at different temperatures was observed by transmission electron microscopy,and the effect of quantum dot annealing on the performance of photodetectors was studied.Finally,a typical Au/PbSe fused quantum dot/Au（100nm）photodetector was successfully developed.The size of quantum dots only 10nm and can be detected by applying an external bias electric field.As the annealing temperature increases,the distance between the quantum dots becomes closer,allowing them to be fused better together.Experimental datas demonstrate that the optimal annealing temperature for the PbSe active layer is 310℃.At this temperature,the switch ratio K and responsivity R both reach to their maximum values,with the responsivity increasing by more than three times.Furthermore,a vertical field-effect phototransistor based on PbSe fused quantum dots was developed for infrared light detection,using Au as the source transparent electrode.Responsivity and specific detectivity reached to 58.53m A/W and4.63×10¹⁰Jones respectively.