Quantum efficiency optimization by maximizing wave function overlap in type-II superlattice photodetectors. Issue 33 (8th August 2017)

• Record Type: Journal Article
• Authors: Zhao, Yunhao; Liu, Lu; Bi, Han; Han, Xi; Zhao, Xuebing; Ni, Haiqiao; Xu, Yingqiang; Niu, Zhichuan; Che, Renchao
• Is Part Of: Nanoscale. Volume 9:Issue 33(2017)
• Page Start: 11833
• Page End: 11840
• Publication Date: 2017-08-08
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/c7nr04319h
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : Appropriate voltage is applied on superlattice photodetector to maximize the wavefunction overlap, which boosts quantum efficiency to its maximum. Abstract : Quantum efficiency (QE) is a crucial parameter that determines the final performance of photodetector devices. Herein, by fitting the charge distribution fluctuation under a series of bias voltages, revealed by groups of in situ electron holography experiments, a simple model based on modulus square of wave function (MSWF) is qualitatively built to shed new light on the relationship between QE and wave function overlap (WFO). It is found that there exists a competition of WFO between the potential well regions and the interface regions, and a peak value of the overall WFO can be obtained under an appropriate voltage. On combining such competition with the measured QE results from actual infrared photodetectors, the positive correlation between QE and WFO is manifested, and the QE can be boosted to 51% from 34%. Our results offer a new perspective to the understanding of the carrier transportation within superlattice (SL) structures and the design on photoelectric devices with enhanced performance.