| Summary: | 碩士 === 國立臺灣科技大學 === 電子工程系 === 107 === In this paper, a photodiode with integrated GaN LED and monitor illuminance is developed, and the basic photoelectric characteristics of the LED the basic photoelectric characteristics of the p-i-n photodetector, and the room temperature of the p-i-n photodiode are measured. The dark current and the photocurrent, responsivity, and light coupling rate produced by the pin photodetector at different distances from the LED.
The p-i-n photodiode and the LED are at different distances and the LED current is increased from 0 mA to 2 mA. When the distance is 1000 μm, the p-i-n photodiode photocurrent is about 2.78*10^(-8)A increased to 7.42*10^(-8) A; when the distance is 2240μm, the photocurrent of the p-i-n photodiode increases from 2.53*10^(-10) to 3.60*10^(-8) A. It can be seen that the photocurrent generated by the p-i-n photodiode increases linearly with the increase of the LED current. In order to know the monitoring responsivity of the p-i-n photodiode, when the p-i-n photodiode operates at 0V bias, the optical power of the LED of 2 mA and the photocurrent measured by the photodiode are respectively taken by the light. The ratio of current to optical power can be used to calculate the monitoring responsivity , and the monitoring responsivity decreases as the distance between the two increases. Next, we discuss the relationship between the optical power of the LED and the monitoring responsivity at a fixed distance. The current of the LED is increased from 0 mA to 2 mA. It can be found that the optical power and the response rate can be almost a certain value. The monitoring responsivity is at a fixed distance of 326 μm, which is between 1.2*10^(-4)A/W to 1.4*10^(-4) A/W. In order to know how much light power the p-i-n photodiode absorbs for different distances of the LED, since the luminous efficiency of each LED is not exactly the same, we will normalize the light power of the LED to 1mW, the responsivity of the p-i-n photodiode can be obtained from the optical power of the incident p-i-n photodiode at different distances, and the ratio of the optical power to the LED is defined as the coupling light ratio. When the LED and the p-i-n photodiode distance is 1000 μm, the coupling light ratio is about 0.83%; and when When the LED and the p-i-n photodiode distance is 5600 μm, only about 0.01% of the light-coupled ratio is obtained. The coupling light rate decreases with distance.
|
|---|
