The Theory Study Of Negative Capacitance In Semiconductor Leds

With the development of industry and technology of semiconductor,light-emitting diodes(LEDs) have been widely used in display, light, light-storage,optical communication, etc. It becomes more and more important to study LEDs'properties carefully. In this paper, we researched the negative capacitance,whichproduces from adding alternating-current in LEDs, and we explained the phenomenaof negative capacitance in LEDs for the first time through basic continuity-equation.Our work can be summarized as follows:1. The limitation in reports about the negative capacitance phenomena was disclosedand discussed.2. We reviewed the basic theories and the properties of LEDs, which provided us thegroundwork to understand the origin mechanism of negative capacitance andcalculate it quantitatively.3. From analyzing a great deal of negative capacitance experiments, we convincedthat the negative capacitance phenomena of LEDs should be caused by its ownproperties instead of other exterior reasons, and negative capacitance should haveclose correlation with radioactive luminescent.4. From analyzing basic continuity-equation we found that the recombination isinductive effect. And we put forward a new model of LEDs and calculated itscapacitance in many conditions by using the Matlab software. At last wecompared the results of theory with the experimental data.5. According to negative capacitance phenomena of other LEDs we corrected ourmodel, the results of our theory agreed with the experiment perfectly. At last weput forward some new questions which will be studied in the future.In conclusion, the quantitative explanation to the negative capacitance of LEDs isvery significant both in theoretical field and in practical application because negativecapacitance of LEDs could possibly induce some important effects on modulationfrequency, switch circuits and so on. This theory might not only complete and developthe forward-transportation theory but also lay the foundation of designing andpreparing new function devices.