随着信息化时代的高速发展，对微电子器件中光电材料的选择、新功能的开发提出了更高的要求。传统光电器件大多利用半导体材料在光照下电导率增加的正光电导性效应进行功能化设计。近年来，研究发现还存在另一种反常的光电导效应——负光电导（Negative photoconductivity，NPC），即在光照条件下电导率降低，由于其在光电探测、逻辑器件、神经形态器件、低功耗非易失性存储器方面的潜在应用而备受关注。NPC的产生机制一般包括载流子的俘获效应、表面分子的吸附-解吸、表面等离子体极化激元和局域表面等离子体共振、光辐射热效应等。本文详细讨论了不同光电器件中NPC产生的物理机制，分析了材料选择、器件结构设计、能带结构变化对不同异质结器件中NPC效应的影响，概括了光电器件中负光电导效应的实际应用，这为光电器件的性能优化和新型光电器件设计提供了重要参考，为未来异质结光电信息器件实现尺寸更小、光导增益更高、速率更快、功耗更低奠定了科学基础。

近年来, 全无机铯铅卤化钙钛矿CsPbX₃(X=Cl, Br, I)纳米晶(NCs)材料因具有长载流子寿命、强光吸收、低成本制造和带隙可调性等独特的性能已成为研究的热点, 但专注于CsPbBr₃纳米晶瞬态光电导的相关研究却很少。本工作通过配体辅助再沉淀法制备了CsPbBr₃纳米晶体, 并改进了光电导薄膜样品的制样方法和真空瞬态光电导测试装置, 研究了不同温度和不同激发功率对CsPbBr₃纳米晶瞬态光电导的影响。不同温度的瞬态光电导实验结果表明, 在133~273 K温度范围内, 光生电流衰减速率随着温度增加而逐渐减小, 而在273~373 K温度范围内, 光生电流衰减速率随着温度升高而逐渐增大。不同激发功率的瞬态光电导实验表明, 激发功率从200 mW逐渐增大到1000 mW时, 光生电流衰减速率增大。本工作的研究方法为研究光激发光生载流子的动力学相关行为提供了一个的新思路。

Transparent conducting aluminum doped tin oxide thin films were prepared by sol-gel dip coating method with different Al concentrations and characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), UV–Vis spectrophotometry and photoconductivity study. The variation observed in the properties of the measured films agrees with a difference in the film's thickness, which decreases when Al concentration augments. X-ray diffraction analysis reveals that all films are polycrystalline with tetragonal structure, (110) plane being the strongest diffraction peak. The crystallite size calculated by the Debye Scherrer’s formula decreases from 11.92 to 8.54 nm when Al concentration increases from 0 to 5 wt.%. AFM images showed grains uniformly distributed in the deposited films. An average transmittance greater than 80% was measured for the films and an energy gap value of about 3.9 eV was deduced from the optical analysis. Finally, the photosensitivity properties like current–voltage characteristics,I_ON/I_OFF ratio, growth and decay time are studied and reported. Also, we have calculated the trap depth energy using the decay portion of the rise and decay curve photocurrent.Transparent conducting aluminum doped tin oxide thin films were prepared by sol-gel dip coating method with different Al concentrations and characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), UV–Vis spectrophotometry and photoconductivity study. The variation observed in the properties of the measured films agrees with a difference in the film's thickness, which decreases when Al concentration augments. X-ray diffraction analysis reveals that all films are polycrystalline with tetragonal structure, (110) plane being the strongest diffraction peak. The crystallite size calculated by the Debye Scherrer’s formula decreases from 11.92 to 8.54 nm when Al concentration increases from 0 to 5 wt.%. AFM images showed grains uniformly distributed in the deposited films. An average transmittance greater than 80% was measured for the films and an energy gap value of about 3.9 eV was deduced from the optical analysis. Finally, the photosensitivity properties like current–voltage characteristics,I_ON/I_OFF ratio, growth and decay time are studied and reported. Also, we have calculated the trap depth energy using the decay portion of the rise and decay curve photocurrent.

基于石墨纳米材料，成功制备金属-石墨-金属结构电磁诱导势阱效应室温太赫兹探测器，实现了高性能的室温太赫兹探测。器件在0.035 THz的响应率达到20 kV/W，在0.1673 THz的响应率达到11 kV/W，器件在0.035 THz的噪声等效功率达到1.25 pW/Hz，在0.1673 THz的噪声等效功率达到2.27 pW/Hz。我们的研究结果为石墨烯太赫兹探测器提供新的思路。