点状PN结中的光电转换

用Ｎ型硅单晶材料制作了点状ＰＮ结光电二极管，对二极管的光电参数进行了测量。若依平面结的受光面积计算，在同样的光辐射下，点状ＰＮ结光岂二极管的光电流密度是常规面积光电二极管光电流密度的２００倍以上。分析表明，在光探测机制上不仅要考虑平面结范围内的光电转换，更要考虑平面结周边一个少数载流子扩散长度范围内的光电转换。利用点状ＰＮ结光照电流的测量，可以 确定在衬底材料光一少了的扩散长度。

Photoelectric conversion in point type PN junction

The point type PN junction photodiodes of silicon are fabricated,and the photoelectric parameters of photodiode are measured.It found that,according to the calculation to the sensitive area with the planar junction,under the same radiation,the light current density of the point type PN junction photodiode is more than that of the photodiode with usual area by a factor of 200.It is shown that,based on the light detection mechanism,the photoelectric conversion is only not taken into account in the planar junction,but also in diffusion length of minority carriers in a periphery of planar junction.By use of light current measurement of point type PN junction,the diffusion length of photogenerated minority carriers in the substrate can be determined.