小面积PN结的光电特性

Photoelectric Character of Small Area PN Junction

用Ｐ型硅材料制作了小面积ＮＰ结光电二极管，测试了二极管的光电特性．若按杂质扩散区的受光面积计算，在同样的光照下，小面积光电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１００倍以上．究其原因，在于杂质扩散区周边一个少数载流于扩散长度范围内，光生载流子对光电流的贡献．因此，当杂质扩散区为一个点时，光敏感区的面积趋于恒定值πＬ，有效光吸收区体积趋于（ＺπＬ）／３．

Abstract The photoelectric character of the small area NP junction of silic on has been investigated. We measured the photocurrent of the device and found that the photocurrent density JLS of the small area NP junction photodiode is much higher than that JLRof the usual area photodiode according to the sensitive area within the dopant diffused region.The super high photocurrent density JLS is due to the contribution of photogenerated minority carriers in the area around the edges of the diffused dopant range to the photocurrent. When the diffused area is a point,the light sensitive area tends to πLn2.