Microcavity Effect in InAs/GaAs Quantum Dot Infrared Photodetector on a Si Substrate Fabricated With Metal Wafer Bonding and Epitaxial Lift-Off Techniques

Abstract

In this paper, the microcavity effect in quantum dot infrared photodetectors (QDIPs) on a Si substrate, fabricated by means of metal wafer bonding (MWB) and epitaxial lift-off (ELO) processes, was demonstrated by comparing the photocurrent spectrum and the simulated absorption spectrum. Four QDIPs having a different cavity length of 1.7, 2.8, 3, and 3.4 μm were fabricated and compared with simulation based on the finite-difference time-domain method. The resonance peaks were observed in both photocurrent spectrum and absorption spectrum due to the microcavity formed by the bottom mirror of Pt/Au layer and the flat GaAs/air interface. The peak wavelength of the photocurrent spectrum in all four QDIPs on Si samples shows a good agreement with the simulated absorption spectrum. The bias-dependent photocurrent was also measured to study the microcavity effects more in depth. The ratio of the increased photocurrent under bias condition shows higher value in the microcavity QDIPs, showing that the microcavity contributes to generate photocurrent effectively. From these results, we believe that the MWB and ELO could be useful to make the microcavity in many integrated chemical and biosensing application.

High-Performance Flexible InAs Thin-Film Photodetector Arrays with Heteroepitaxial Growth Using an Abruptly Graded InxAl1–xAs Buffer

“…In addition, several resonant peaks were observed in the spectral responsivity of the flexible PD, which were positioned at around 2.85 and 3.4 μm. We think that it is due to the micro-cavity effect in the two mirrors of Pt/Au bonding material and InAs/air interface. ,, Figure c shows the noise current level of the flexible device. The specific detectivity of flexible InAs PD is defined as where A is the window size of the device, Δ f is the bandwidth, and i n is the noise current of the device.…”

“…We think that it is due to the microcavity effect in the two mirrors of Pt/Au bonding material and InAs/air interface. 14,35,36 Figure 6c shows the noise current level of the flexible device. The specific detectivity of flexible InAs PD is defined as…”