Responsivity and detectivity enhancements by graphene overlay on normal-incident multicolor quantum grid infrared photodetectors

Abstract

An efficient and effective method to achieve high responsivity and specific detectivity, particularly for normal-incident quantum well infrared photodetectors (QWIPs), is proposed in this study. By combining superlattice (SL) structure, grating structures, and graphene monolayer onto traditional QWIP designs, a graphene-covered multicolor quantum grid infrared photodetector (QGIP) with improved optoelectrical properties is developed. The enhancements of the device’s responsivity and specific detectivity are about 7-fold and 20-fold, respectively, which resulted from an increase in the charge depletion region and the generation of extra photoelectrons due to graphene-semiconductor heterojunction. This method provides a potential candidate for future high-performance photodetectors.

Resonance-Enhanced Quantum Well Micropillar Array with Ultra-Narrow Bandwidth and Ultra-High Peak Quantum Efficiency

“…Specialized optical modulation structures need to be designed to meet the unique requirement of QWIPs for vertically polarized light. Current researchers usually design grating-type QWIP structures [9][10][11][12][13] or corrugated QWIP structures [14,15] to meet the conditions for the absorption of normal incident light by QWIPs. However, the low efficiency of optical coupling dramatically limits the sensitivity of the device.…”