基于硫化铅量子点的近红外光电二极管研究

Research on Near Infrared Photodiode Based on Lead Sulfide Quantum Dots

李晨昊

11749116

硕士

物理电子学

王恺

2019-05-24

2019-07-10

哈尔滨工业大学

深圳

硫化铅晶体的能量带隙为0.41eV，可以探测到波段为3μm的红外辐射，是常用的近红外探测器材料之一。当硫化铅晶体的粒径尺寸缩小到几到几十纳米，与其波尔半径相似时，会发生量子限域效应，硫化铅原本连续的能级发生分立，并产生了一系列的奇特的光电效应：更高消光系数，吸收峰位可调谐和更宽的吸收谱等。硫化铅量子点由于制备方法简单、成本低廉、探测灵敏度高、吸收峰位可调谐等优点，被研究人员视为新一代的近红外探测器材料。本文主要研究内容为基于硫化铅量子点材料的近红外光电二极管的制备和优化。对硫化铅量子点湿法工艺中的成膜质量进行了研究，制备了近红外的光电探测器并对器件性能进行了测试和优化。取得的成果如下：（1） 探究了硫化铅量子点在不同溶剂体系下旋涂的成膜性，发现过滤次数和提纯次数的多少都会对量子点成膜效果产生影响。（2）制备了基于硫化铅量子点材料的光电导探测器，器件灵敏度可以达到486 mA/W，比探测率为2.67×1011Jones。（3）制备了基于硫化铅量子点材料的光电二极管，器件灵敏度为0.262 A/W，900nm的红外光外量子效率达到36.1%。但是在外加电压大于1V时漏电情况较为严重，影响器件的性能。（4）对硫化铅量子点光电二极管进行了分析，为解决漏电流问题引入了PVK作为阻挡层对暗电流进行了限制，使得暗电流与之前相比下降了两个数量级。对由于量子点薄膜配体交换而导致的薄膜龟裂问题进行了探究性实验并发现溶剂的挥发性、粘滞度、极性、清洗方式等因素都会对薄膜质量产生影响，通过优化溶剂和调控旋涂气氛等方式提高了薄膜质量。本文对硫化铅光电二极管的制备方法与制备工艺进行了优化研究，探索了硫化铅量子点薄膜质量的优化方式，为以后硫化铅量子点光电探测器的研究提供给了思路。

The energy band of the lead sulfide crystal is 0.41eV, and can detect infrared radiation with a wavelength of 3μm, which makes PbS a commonly used near-infrared detector material. When the particle size of lead sulfide crystals is reduced to a few to several tens of nanometers, similar to its Bohr radius, its energy level is separated due to the quantum confinement effect and produces a series of peculiar photoelectric effects: high extinction coefficient, the absorption peak increases as the quantum dot size becomes smaller, and a broad absorption spectrum. The lead sulfide quantum dots are considered by the researchers as a new generation of near-infrared detector materials due to their simple manufacturing method, low cost and high detection sensitivity. The main content of this paper is the preparation and optimization of near-infrared photodiodes based on lead sulfide quantum dot materials. The film formation in the lead sulfide quantum dot wet process was studied. The near-infrared photodetector was fabricated and the device performance was tested and optimized. The following results have been achieved: (1) The spin-filming properties of lead sulfide quantum dots in different solvent systems were investigated. The appropriate number of times of filtration and the number of purifications have an effect on the quality and film-forming properties of quantum dots. (2) Photoconductive detectors with lead sulfide quantum dot materials have been prepared, and their performance can be achieved 486mA /W, detectivity is 2.67×1011Jones. (3) The photodiode of lead sulfide quantum dot material is prepared, and the performance is 0.262 A/W, 900nm infrared light external quantum efficiency reaches 36.1%. But the leakage condition is severe under high voltage, which affects the use of the guiding device. (4) The optimization theory of lead sulfide quantum dot photodiodes was analyzed, and an optimization solution was proposed based on the previous leakage current problem. The investigation of the film cracking caused by the exchange of quantum dot film ligands and the solvent volatility, viscosity, polarity, cleaning method, etc. all have an effect on the film quality. The quality of the film can be improved by changing the solvent and adjusting the atmosphere in the spin-coating room. In this thesis, the preparation method of lead sulfide photodiode is studied, the preparation process is optimized, and the optimization method of quantum dot film quality is explored, which provides ideas for the research and industrialization of lead sulfide quantum dot photodetectors.

硫化铅量子点 光电二极管 器件结构优化 薄膜质量优化

Lead sulfide quantum dots photodiodes device structure optimization film quality optimization

中文

联合培养

南方科技大学

李晨昊. 基于硫化铅量子点的近红外光电二极管研究[D]. 深圳. 哈尔滨工业大学,2019.