SBIR-STTR Award

The proposed research program focuses on design, fabrication, and characterization of quantum-dot infrared photodetectors (QDIPs) which features bias-tunable parameters, including the spectral response, optical gain, and operating time. Wide variations of detector parameters can be realized through the bias-tunable potential barriers surrounding quantum dots. Changes in bias will transform the band structure and modify the population of electron states in quantum dots. These quasi-localized electrons create local and collective potential barriers, which in turn may significantly change the photoelectron capture and spectral characteristics. Specific tasks include (i) advanced modeling of regimes with bias-tunable barriers and search for optimal design (geometry, selective doping etc); (ii) fabrication and characterization of QD structures with selective doping favorable for bias-tunable barriers; (iii) measurements of detector parameters; (vi) optimization of structures and operating regimes. By investigating essential nanoscale phenomena in QD structures, we expect to develop an adequate description of electron kinetics and transport. By providing the needed base, this program will have a strong impact on the development of adaptive QDIPs.

Benefit:
Multispectral infrared remote sensing is an advancing technology with numerous applications, including detection of specific objects based on differences of their IR spectra relative to the background. Bias-tunable spectral functions and electron kinetics in quantum dot IR photo-detectors will allow of fabricating focal plane arrays with adaptive pixel under voltage control.

Keywords:
Quantum Dot, Photo-Detector, Tunable, Infra-Red, Spectrum

Esensors, with SUNY at Buffalo and SUNY at Albany as a subcontractor, will simulate, fabricate, experimentally investigate, evaluate, and deliver aprototype of a new adaptive IR photodetector based on advanced quantum dot (QD) structures. The detector’s operating principle is based on a new concept of the photoelectron lifetime tunable via adjustable potential barriers in QD structures. The photoelectron kinetics and corresponding noise processes will be investigated in specially designed and fabricated QD structures with lateral and vertical transport, which is controlled by specific potential barriers created by charged QD rows, planes and clusters. Tuning the photocarrier lifetime by the bias and/or gate voltages will allow for new intriguing possibilities for adaptive sensing and imaging with optimal data acquisition via controllable interplay of basic parameters: operating time vs.sensitivity. The proposed detectors will have the advantages: (a) tunable photoelectron kinetics, which allows for adaptive operating regimes; (b) adjustable highly-selective coupling to electromagnetic radiation due to control of QD levels and their occupations; (c) high phoconductive gain and responsivity; (d) low generation-recombination noise; (e) high scalability of nanoblocks and numerous possibilities for nano-engineering; (f) high mobility of carriers and low dissipation; (g) technological compatibility with mainstream manufacturing.

Benefit:
The structured quantum dot detector provides an important fundamental building block to IR system developers offering increased sensitivity, lower noise at a competitive cost. The improvements in sensitivity/signal-to-noise are estimated by our research team to be better than 100 times better than product currently available at a comparable price. This advanced mid-IR detector will result in development of a new generation of high sensitivity IR detectors and imagers. Immediate applications exist in three market areas: scientific measurement, military surveillance and chemical-biological (includes medical).

Keywords:
Quantum Dot, Infrared, Sensor, High Sensitivity, Room Temperature