Quantum dot infrared photodetectors

TitleQuantum dot infrared photodetectors
Publication TypeJournal Article
Year of Publication2002
AuthorsP Bhattacharya, AD Stiff-Roberts, S Krishna, and S Kennerly
JournalSmart Structures and Materials 2005: Active Materials: Behavior and Mechanics
Start Page100
Pagination100 - 109
Date Published01/2002

Mid-and far-infrared detectors operating at elevated temperatures (T > 150 K) are critical for imaging applications. In(Ga)As/GaAs quantum dots, grown by self-organized epitaxy, are an important material for the design and fabrication of high-temperature infrared photodetectors. Quantum dot infrared photodetectors (QDIPs) allow normal-incidence operation, in addition to low dark currents and multispectral response. The long intersubband relaxation time of electrons in quantum dots improves the responsivity of the detectors, contributing to better high-temperature performance. These devices also exhibit photoconductive gain. The characteristics of state-of-the-art lateral and vertical QDIPs will be described. We have achieved peak responsivity for wavelengths ranging from 3.7-18 μm. We have also obtained extremely low dark currents (Idark = 27 pA, T = 100 K, Vbias = 0.5 V), high detectivities (D* = 2.9×108 cmHz1/2/W, T = 100 K, Vbias = 0.2 V), and high operating temperatures (T = 150 K) for these quantum-dot detectors. The excellent performance of these devices at low bias voltages indicates the compatibility of high-temperature QDIPs with commercially available silicon read-out circuits for imaging focal plane arrays. These results, as well as infrared imaging with QDIP arrays, will be described and discussed. © 2002 SPIE · 0277-786X/02/$15.00.

Short TitleSmart Structures and Materials 2005: Active Materials: Behavior and Mechanics