In this presentation, the effects of AuGe nanoparticles formation on the properties of GaAs films and bilayer InAs/GaAs quantum dots heterostructure will be discussed. The AuGe nanoparticles formation was done by thin films deposition using e-beam evaporation followed by rapid thermal annealing process. Optimization of annealing conditions in terms of optical and morphological properties of these samples has been performed. Scanning electron microscopy confirmed the formation of AuGe nanoparticles on the sample surface. Optical absorption spectroscopy revealed the plasmon resonance peak of AuGe nanoparticles at around 670 nm for the sample annealed at 300 oC, confirming the presence of the plasmonic effect. Compared to the uncovered sample, a maximum enhancement of 58% in photoluminescence (PL) intensity was observed for AuGe-deposited sample annealed at 300 °C. Subsequently, we successfully fabricated AuGe plasmonic-based heptalayer coupled InGaAs quantum dot infrared photo-detector. For device sample, we did our investigation for PL spectra of heptalayer samples having AuGe nanoparticles for different annealing temperature to optimize efficient light coupling for higher PL intensity. We achieved two-order and one-order increments in peak responsivity and detectivity, respectively, at 80 K. The enhancements are attributed to increased light trapping in the device and strong plasmonic-QD interaction by the AuGe nanoparticles. This demonstration will accelerate further development of high-performance quantum dot infrared photo-detectors.
Dr. Sushil Kumar Pandey is a post-doctoral fellow in Electrical Engineering department of Indian Institute of Technology Bombay. He completed his PhD degree in 2015 in Electrical Engineering department of Indian Institute of Technology Indore. His research interests are in plasmonic-based infrared photo-detectors.