Magnolia Optical Technologies, Inc.

John W Zeller

Ashok K Sood

Yash R Puri

A high-performance Microbolometer that incorporates vanadium oxide (VOx) along with carbon nanotubes (CNTs) or graphene. This Microbolometer, which uses a microbridge comprising Si3N4 and VOx, provides low noise and high dynamic range longwave infrared (LWIR) band detection. Addition of CNTs/graphene provides a high level of performance [low 1/f noise, noise equivalent temperature difference (NETD), and thermal time constant] due to the high temperature coefficient of resistance (TCR) of these materials.

High-performance microbolometer using VOx, CNT and graphene for longwave infrared (LWIR) applications

Through selective incorporation of high carrier mobility graphene monolayers into low cost, NIR-sensitive SiGe detector layer structures, a device combining beneficial features from both technologies can be achieved. The SiGe in such hybrid SiGe/graphene detector devices serves as the NIR absorbing layer, or as the quantum dot material in certain device iterations. The bandgap of this SiGe layer where absorption of photons and photogeneration of carriers mainly takes place may be tuned by varying the concentrations of Ge in the SixGe1-x material. This bandgap and the thickness of this layer largely impact the degree and spectral characteristics of absorption properties, and thus the quantum efficiency or responsivity of the device. The main function and utility of the graphene monolayers, which are nearly transparent to incident light, is to facilitate the extraction and transport of electron and hole carriers from the SiGe absorbing layer through the device.

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Woburn, MA, United States of America

John W Zeller