Influence of AlGaN/GaN interface polarization fields on the properties of photoconductive detectors.

The Al 0.22 Ga 0.78 N/GaN/Al 0.22 Ga 0.78 N multilayer heterostructure photoconductive detectors were designed and fabricated. The influence of AlGaN/GaN interface polarization fields on the properties of the photodetector was investigated. The energy band profile of the heterostructure was approximately calculated. Results indicate that electron and hole wells exist on the GaN sides of the Al 0.22 Ga 0.78 N/GaN/Al 0.22 Ga 0.78 N interfaces. The existence of two-dimensional electron gas was proved by variable temperature Hall measurements. The spectral response shows that the responsivity of the heterostructure photodetector was as high as 43 00 A/W at 355 nm under 3 V bias, which is nearly ten times higher than that of a GaN monolayer structure photodetector. [ABSTRACT FROM AUTHOR]