Future Trends in Microelectronics: From Nanophotonics to Sensors to Energy

Quantum-Dot Infrared Photodetectors: In Search of the Right Design for Room-Temperature Operation

A. Sergeev, V. Mitin, L. H. Chien, and N. Vagidov

Dept. of Electrical Engineering, SUNY-Buffalo Buffalo, NY 14260, U.S.A.

1.   Introduction

Development of sensitive low-cost far-infrared photodetectors is critical for various applications in public safety, industry, healthcare, and defense technologies.^1,2,3 Sensitive detectors operating at the room temperature would significantly increase both commercial and defense markets, where the quantum-well infrared photodetectors (QWIPs) currently prevail over other sensors. The advantages of QWIPs include low cost, high uniformity and reproducibility due to well-established GaAs growth and processing technologies. Large area QWIP arrays are employed in imaging devices operating at liquid nitrogen temperatures and below.⁴ Modern QWIPs demonstrate the detectivity of ~10¹⁰ cmHz^1/2/W for λ = 10 μm at 77 K. However, the detectivity drops to 10 cm Hz^1/2/W at room temperature. It is well understood that the high-temperature limitations of QWIPs and many other photodetectors are caused by a tremendous decrease of the photocarrier lifetime, which strongly reduces the responsivity and sensitivity.⁵

Quantum-dot infrared photodetectors (QDIPs) were proposed by Ryzhii⁶ in 1996. Since then, QDIPs have been considered the most promising candidate for achieving room-temperature operation. Initially, these hopes were pinned on the long photoexcited electron ...