Title :
Significant Performance Improvement in AlGaN Solar-Blind Avalanche Photodiodes by Exploiting the Built-In Polarization Electric Field
Author :
Zhenguang Shao ; Dunjun Chen ; Yanli Liu ; Hai Lu ; Rong Zhang ; Youdou Zheng ; Liang Li ; Kexiu Dong
Author_Institution :
Key Lab. of Adv. Photonic & Electron. Mater., Nanjing Univ., Nanjing, China
Abstract :
We present improved AlGaN solar-blind avalanche photodiodes (APDs) with a separate absorption and multiplication (SAM) structure by introducing a polarization electric field with the same direction as reverse bias field in the multiplication region. This polarization electric field can be realized by reducing the Al composition of the p-AlGaN layer in a conventional p-i-n-i-n SAM-APD structure. After employing a reduced-Al-composition p-AlGaN instead of the commonly used p-AlGaN, the polarization enhanced APD exhibits a markedly lower avalanche breakdown voltage and a near two times higher avalanche gain up to 2.1 × 104 compared with its conventional counterpart. In addition, X-ray diffraction and transmission electron microscopy results show that a moderate reduction of Al composition in the p-AlGaN layer does not degrade the crystalline quality of the polarization enhanced APD structure resulted from lattice mismatch, which guarantees the polarization enhanced effect.
Keywords :
III-V semiconductors; X-ray diffraction; aluminium compounds; amplification; avalanche breakdown; avalanche photodiodes; gallium compounds; transmission electron microscopy; APD; AlGaN; AlGaN solar-blind avalanche photodiodes; X-ray diffraction; absorption structure; avalanche breakdown voltage; avalanche gain; built-in polarization electric field; crystalline quality; lattice mismatch; multiplication structure; polarization enhanced effect; reverse bias field; transmission electron microscopy; Aluminum gallium nitride; Avalanche breakdown; Avalanche photodiodes; Breakdown voltage; Educational institutions; Electric fields; Strain; AlGaN; avalanche photodiodes; avalanche photodiodes (APDs); polarization electric field; solar blind;
Journal_Title :
Selected Topics in Quantum Electronics, IEEE Journal of
DOI :
10.1109/JSTQE.2014.2328437