MIOMD-XI Speakers    
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1.  Mr. Robert Hinkey, Univ of Oklahoma, USA
Late-Breaking Results: Dark current modeling of interband cascade infrared photodetectors
Speaker Biography: Mr. Robert Hinkey was born in Baltimore, Maryland in 1985. He received a Bachelor of Science in Physics in 2007 from Loyola College in Maryland. Since 2008, he has worked in the OU Quantum Devices group under Prof. Rui Yang, conducting research on semiconductor devices based on quantum structures. He received a Master's Degree from the University of Oklahoma in Engineering Physics, and is currently pursuing the Ph.D degree, which he aims to complete in 2013. His doctoral dissertation topic is the design, modeling, and characterization of interband cascade structures for mid-infrared photodetectors and photovoltaic devices for energy conversion. He also collaborates with other members of the group on the development of long-wavelength interband cascade lasers.

Summary: Interband cascade infrared photodetectors (ICIPs) employ a flexible device architecture designed to overcome short diffusion lengths and achieve high performance in photovoltaic devices based on InAs/GaSb superlattice (SL) absorbers. This is done by substituting the standard long single absorber (typically > 2.0 μm) for a group of shorter discrete absorbers (e.g. 0.1-0.2 μm). The conduction and valence bands of adjacent absorbers are connected in series using an interband tunneling heterostructure. This heterostructure consists of an electron barrier formed from GaSb/AlSb quantum wells (QWs) and a hole barrier formed from InAs/AlSb QWs, and is designed to facilitate a preferred carrier transport direction. The absorbers are sandwiched between the interband tunneling heterostructures, and the device exhibits the rectifying behavior required for photovoltaic operation. This architecture is similar to the “stacked multijunction” approach, which has been proposed in the past for realizing uncooled operation in MCT-based photovoltaic detectors, but has not received much attention in the literature. In this work, we will present our initial efforts in modeling ICIPs under non-equilibrium conditions. Here, we focus on the case where the dark current is solely due to generation-recombination processes in the absorber. The thermalization of carriers (due to drift-diffusion processes) within the absorber and interband tunneling heterostructure region is assumed to occur on a timescale much faster than the generation-recombination processes. Under this approximation, the holes within the valence band of one absorber are in equilibrium with the electrons in the previous absorber, and thus share a common chemical potential.
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