246nm p-i-n型背照AlGaN太阳盲紫外探测器的研制

Fabrication of 246 nm back-illuminated AlGaN solar-blind ultraviolet p-i-n photodetector

设计并制备出短波长p-i-n型背照AlGaN太阳盲紫外探测器,响应波段为225～255 nm,峰值波长为246nm。材料为在蓝宝石衬底上生长的背照式p-i-n型异质结结构,n型窗口层的AlxGa1-xN中的Al组分为71%,非故意掺杂吸收层中的Al组分为52%。零偏压下测得的暗电流为27 pA,光电流为2.7 nA,峰值响应度为23 mA/W。并在此基础上制备出大面阵太阳盲紫外探测器芯片,其像元数为128×128,光敏元直径为44μm,像元间距为50μm。

A short wavelength back-illuminated A1GaN solar-blind ultraviolet p-i-n photodetector was designed and fabricated. It was photosensitive in the waveband 225-255 nm, and the peak wavelength was 246 nm. A back-illuminated p-i-n heterojunction structure was grown on transparent sapphire substrate using MOCVD, the AIxGal_xN alloy composition of the n-type window layer was 71%, and the alloy composition of the unintentionally doped （UID） absorber layer was 52%. The dark current measured at zero bias was 27 pA, and the photocurrent was 2.7 nA, while the peak responsivity was 23 mA/W. A 128×128 pixels solar blind ultraviolet photodetector array was fabricated on this basis. The diameter of each pixel was 44μm with a 50 μm pitch.