Polarization enhanced photoresponse of AlGaN p-i-n photodetectors

• Published in: Physica status solidi. A, Applications and materials science Vol. 212; no. 3; pp. 698 - 702
• Main Authors: Yang, Lian-hong, Lai, Kang-rong, Zhang, Bao-hua, Fu, Xiao-ling, Wang, Jun-jun, Wei, Wei
• Format: Journal Article
• Language: English
• Published: Weinheim Blackwell Publishing Ltd 01.03.2015; Wiley Subscription Services, Inc
• Subjects: AlGaN; Aluminum; Aluminum gallium nitrides; Composition effects; Construction; Photocurrent; Photodetectors; Polarization; Spectra
• ISSN: 1862-6300; 1862-6319
• DOI: 10.1002/pssa.201431506

We fabricated an enhanced photoresponse AlGaN p–i–n photodetector by introducing a polarization electric field along the growth direction into the active layer. The polarization‐enhanced effect was realized by reducing Al composition of the p‐AlGaN layer with respect to that of the i‐ and n‐type layers. The simulated results of energy‐band structure and electric‐field distribution indicate that the polarization‐enhanced structure can increase greatly the build‐in field in the active region and hence improve the collection efficiency of photogenerated carriers. The measured photocurrent spectra show that the polarization‐enhanced photodetector exhibits a nearly three times higher responsivity and a larger UV/visible contrast than its conventional counterpart.