白光LED在提供室内照明的同时可被用作通信光源进而有望实现室内无线高速数据接入, 并有望成为下一代高速无线通信的模式。利用KEIL软件实现了基于单片机STC89C52的无线可见光发射机的设计, 采用脉冲位置调制(PPM)编码方式对数据进行了调制编码, 并通过电路搭建和实验测试验证了该系统的可行性。

The current-voltage (I-V) characteristics of 4H-SiC metal-semiconductor-metal (MSM) ultraviolet photodetector with different finger widths and spacings, different carrier concentrations and thicknesses of n-type epitaxial layer are simulated. The simulation results indicate that the dark current and the photocurrent both increase when the finger width increases. But the effect of finger width on the dark current is more significant. On the other hand, the effect of finger spacing on the photocurrent is more significant. When the finger spacing increases, the photocurrent decreases and the dark current is almost changeless. In addition, it is found that the smaller the carrier concentration of n-type epitaxial layer is, the smaller the dark current and the larger the photocurrent will be. It is also found that I-V characteristics of MSM detector also depend on the epitaxial layer thickness. The dark current of detector is smaller and the photocurrent is larger when the epitaxial layer thickness is about 3 \mum.

用MEDICI软件对金属-半导体-金属(MSM)结构4H-SiC紫外(UV)探测器的I-V特性以及光谱响应等特性进行了模拟与分析,并探讨了金属电极的宽度、电极间距以及外延层厚度对探测器响应度的影响。结果表明,室温下该探测器的暗电流线性密度达到10-13 A/μm,且在不同电压下光电流至少比暗电流大两个数量级; 探测器的光谱响应范围为200～400 nm,在347 nm处响应度达到极大值; 增大指宽或者减小指间距可以提高探测器的响应度; 当波长小于峰值波长时外延层厚度对探测器的响应度基本没影响,而当波长大于峰值波长时随着外延层厚度的增大探测器的响应度有所增大。

研究了激光辐照下约瑟夫森结的直流I-V特性变化,并对Ⅰ-Ⅴ曲线下移的实验结果进行了分析,认为是光拆库柏对效应所致.该结果为发展一种新的可见光探测器提供了思路.