David L Spears, 83Freedom, NH

6452206, Sep 17, 2002

Mar 16, 1998

09/039602

Theodore C. Harman - Lexington MA
Mildred S. Dresselhaus - Arlington MA
David L. Spears - Acton MA
Michael P. Walsh - Lunenberg MA
Stephen B. Cronin - Cambridge MA
Xiangzhong Sun - Cambridge MA
Takaaki Koga - Cambridge MA

Massachusetts Institute of Technology - Cambridge MA

H01L 29225

257 22, 257 17, 257183, 257467, 257614, 257930

A superlattice structure for thermoelectric power generation includes m monolayers of a first barrier material alternating with n monolayers of a second quantum well material with a pair of monolayers defining a superlattice period and each of the materials having a relatively smooth interface therebetween. Each of the quantum well layers have a thickness which is less than the thickness of the barrier layer by an amount which causes substantial confinement of conduction carriers to the quantum well layer and the alternating layers provide a superlattice structure having a figure of merit which increases with increasing temperature.

7920261, Apr 5, 2011

Feb 11, 2008

12/029300

Thomas H. Jeys - Lexington MA, US
Antonio Sanchez-Rubio - Lexington MA, US
Richard J. Molnar - Harvard MA, US
Robert K. Reich - Tyngsborough MA, US
Jinendra K. Ranka - Westford MA, US
David L. Spears - Acton MA, US

Massachusetts Institute of Technology - Cambridge MA

G01N 21/00

356338, 356 73

A particle detection system that images and detects particles in a fluid flow stream through use of detector array(s) is described. The detection system may include light source arrays that may selectively illuminate a particle in a fluid stream. The detection system may also include a detector array employing smart binning to read the measured signals. The smart binning of the detector array may be achieved through knowledge of an exact particle location provided by a position sensitive detector. The detector array(s) may be low cost based on intelligence built into the system. This particle detection system may be particularly useful for detection and discrimination of different particle types since the read-out of the particle signals can be accomplished with low noise and can be flexible enough to optimize the read out measurements for each particle. The particle detection system may be used, for example, in early warning contamination detection systems and manufacturing processes.

5455421, Oct 3, 1995

Aug 13, 1985

6/765316

David L. Spears - Acton MA

Massachusetts Institute of Technology - Cambridge MA

G01J 520
H01L 2714

2503384

A photodetector for detecting optical irradiation at a predetermined wavelength is provided with an integral, resonant optical cavity by forming a plurality of layers of material on a metallic reflector backing, the total optical thickness of those layers being an odd multiple of one-quarter of the predetermined wavelength. One of those layers is an active (i. e. optically-absorptive) semiconductor material. When the materials are deposited, that absorbing layer is formed at a level in the cavity including a region of peak optical field. As a result of the enhanced absorption provided by the resonant structure, the active layer may be very thin (i. e. , less than one-tenth of a wavelength thick), yielding many beneficial results.