用发光二极管的电致发光过程测普朗克常量

Measuring Planck Constant in Electroluminescent Process of LED

按光电效应原理普朗克常量可通过光电倍增管的反向截止电压测得,由于受环境光以及光电管本身噪声电流的影响,结果的精度不够理想。而发光二极管是在外界电场作用下通过PN结上的载流子相互复合产生自发辐射,辐射光子的能量直接决定于外加二极管的正向导通阈值电压,不受外界因素的影响,因此能得到较理想的结果。

Plank constant can be determined by measuring the reversed cut-off voltage of photomultiplier according to the principle of photoelectric effect.But the experiment accuracy is not so good because of environmental light and current noises.While LED emits spontaneous radiation by the current carrier recombination under the external electrical field.Its photon energy is up to the threshold voltage,not to do with environmental factors,so the result is great satisfactory.