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Direct minority carrier transport characterization of InAs/InAsSb superlattice nBn photodetectors

Applied Physics Letters

Zuo, Daniel; Liu, Runyu; Wasserman, Daniel; Mabon, James; He, Zhao Y.; Liu, Shi; Zhang, Yong H.; Kadlec, Emil A.; Olson, Benjamin V.; Shaner, Eric A.

We present an extensive characterization of the minority carrier transport properties in an nBn mid-wave infrared detector incorporating a Ga-free InAs/InAsSb type-II superlattice as the absorbing region. Using a modified electron beam induced current technique in conjunction with time-resolved photoluminescence, we were able to determine several important transport parameters of the absorber region in the device, which uses a barrier layer to reduce dark current. For a device at liquid He temperatures, we report a minority carrier diffusion length of 750 nm and a minority carrier lifetime of 200 ns, with a vertical diffusivity of 3 × 10-2 cm2/s. We also report on the device's optical response characteristics at 78 K.

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TYPE Journal Article YEAR 2015
ScopusOSTIDOI

Microwave conductance of aligned multiwall carbon nanotube textile sheets

Applied Physics Letters

Brown, Brian L.; Bykova, Julia S.; Howard, Austin R.; Zakhidov, Anvar A.; Shaner, Eric A.; Lee, Mark

Multiwall carbon nanotube (MWNT) sheets are a class of nanomaterial-based multifunctional textile with potentially useful microwave properties. To understand better the microwave electrodynamics, complex AC conductance measurements from 0.01 to 50 GHz were made on sheets of highly aligned MWNTs with the alignment texture both parallel and perpendicular to the microwave electric field polarization. In both orientations, the AC conductance is modeled to first order by a parallel frequency-independent conductance and capacitance with no inductive contribution. This is consistent with low-frequency diffusive Drude AC conduction up to 50 GHz, in contrast to the "universal disorder" AC conduction reported in many types of single-wall nanotube materials.

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TYPE Journal Article YEAR 2014
ScopusOSTI

Active Control of Nitride Plasmonic Dispersion in the Far Infrared

Shaner, Eric A.; Dyer, Gregory C.; Seng, William F.; Bethke, Donald T.; Grine, Albert D.; Baca, A.G.; Allerman, A.A.

We investigate plasmonic structures in nitride-based materials for far-infrared (IR) applications. The two dimensional electron gas (2DEG) in the GaN/AlGaN material system, much like metal- dielectric structures, is a patternable plasmonic medium. However, it also permits for direct tunability via an applied voltage. While there have been proof-of-principle demonstrations of plasma excitations in nitride 2DEGs, exploration of the potential of this material system has thus far been limited. We recently demonstrated coherent phenomena such as the formation of plasmonic crystals, strong coupling of tunable crystal defects to a plasmonic crystal, and electromagnetically induced transparency in GaAs/AlGaAs 2DEGs at sub-THz frequencies. In this project, we explore whether these effects can be realized in nitride 2DEG materials above 1 THz and at temperatures exceeding 77 K.

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TYPE SAND Report YEAR 2014
OSTIDOI
Results 51–75 of 179
Results 51–75 of 179