Quantum dot photonic crystal detectors

Abstract

In this paper we report the use of a photonic crystal resonant cavity to increase the quantum efficiency, detectivity (D*) and the background limited infrared photodetector (BLIP) temperature of a quantum dot detector. The photonic crystal is incorporated in InAs/InGaAs/GaAs dots-in-well (DWELL) detector using Electron beam lithography. From calibrated blackbody measurements, the conversion efficiency of the detector with the photonic crystal (DWELL-PC) is found to be 58.5% at-2.5 V while the control DWELL detectors have quantum efficiency of 7.6% at the same bias. We observed no significant reduction in the dark current of the photonic crystal devices compared to the normal structure. The generation-recombination limited D* at 77K with a 300K F1.7 background, is estimated to be 6 x 10 10 cmHz 1/2 /W at-3V bias for the DWELL-PC which is a factor of 20 higher than that of the control sample. We also observed a 20% increase in the BLIP temperature for the DWELL-PCs.

New concepts in infrared photodetector designs

“…Most existing devices are realized as two-dimensional (2D) PC structures, as they are compatible with standard semiconductor processing. [24][25][26] PC crystal represents a regular array of holes (defects) that is used to modify the local refractive index to provide localized modes in the "photonic" band structure (see Fig. 10).…”

HOT infrared photodetectors

“…So, broadband absorption is usually inadequate due to quantum efficiency roll−off. To improve charge collection of photons with varying wavelengths application, the pho− tonic crystals to IR detectors are applied [31]. Krishna et al [32] have reported quantum efficiency improvement from 7% to 93% for reverse biased DWELL detector.…”

“…Photon trapping detectors have been demonstrated inde− pendently in II-VI and III-V based epitaxial materials [31][32][33][34]. Sub−wavelength size semiconductor pillar arrays within a single detector are designed and structured as an ensemble of 3D photonic structure units using either a top− −down or bottom−up process scheme to significantly in− crease absorption and quantum efficiency.…”