Anne Wegmann

Bio: Anne Wegmann is an academic researcher. The author has contributed to research in topics: Optoelectronics & Plasmon. The author has an hindex of 1, co-authored 2 publications receiving 2 citations.

Quantum Efficiency and Crosstalk in Subwavelength HgCdTe Dual Band Infrared Detectors

Abstract: This work investigates the spectral quantum efficiency and inter-pixel crosstalk of a MWIR-LWIR dual band, HgCdTe-based focal plane array (FPA) photodetector (MWIR and LWIR stand for mid- and long-wavelength infrared bands) Pixels are $\text{10}\,\mu$ m-wide with truncated pyramid geometry and separated by deep trenches Three-dimensional combined full-wave electromagnetic and electrical simulations in the drift-diffusion approximation allowed to describe the complex, standing-wave-like spectral features resulting from the light interference and diffraction due to the pixels and illuminating beam aperture The inter-pixel crosstalk for the MWIR operation demonstrated to be very sensitive to the trench depth, in contrast to the LWIR electrooptical response, left almost unchanged The present work also investigates the causes of performance worsening in the two IR bands when pixel pitch is reduced to $\text{5}\,\mu$ m, hence well below typical LWIR wavelengths and close to the diffraction limited operation

Plasmon-Enhanced Light Absorption in Mid-Wavelength Infrared HgCdTe Detectors

Abstract: Multiphysics modeling of a planar HgCdTe-based mid-wavelength infrared (MWIR) focal plane array with $3\,\mu$ m-wide pixels enlightens the role of surface plasmon-polaritons observed in gold nanorods arranged on its illuminated face. Simulations indicate that the proposed plasmonic detector, which employs a $1\,\mu$ m-thick absorber layer, exhibits a reduction of diffusive inter-pixel crosstalk by more than one order of magnitude with respect to more conventional, non-plasmonic detectors with a $5\,\mu$ m-thick absorber layer, without penalizing responsivity and achieving increased detectivity in the whole MWIR band by taking advantage of the absorber volume reduction.

SRH suppressed P-G-I design for very long-wavelength infrared HgCdTe photodiodes.

Abstract: The very long wavelength infrared (VLWIR, >14 µm) spectral band is an indispensable part of new-generation infrared remote sensing. Mercury cadmium telluride (HgCdTe or MCT) has shown excellent potential across the entire infrared band. However, the dark current, which is extremely sensitive to the technological level and small Cd composition, severely limits the performance of VLWIR HgCdTe photodiodes. In this study, cut-off wavelengths of up to 15 µm for HgCdTe devices with novel P-G-I (including wide bandgap p-type cap layer, grading layer and intrinsic absorption layer) designs have been reported. Compared with a device with a double-layer heterojunction (DLHJ) structure, the designed P-G-I structure successfully reduced dark current by suppressing the Shockley-Read-Hall process. Considering the balance of quantum efficiency and dark current, with the introduction of an approximately 0.8 µm thickness Cd composition grading layer, the device can achieve a high detectivity of up to 2.5×1011 cm Hz1/2 W-1. Experiments show that the P-G-I-T device has a lower dark current and a better SRH process suppressing ability than DLHJ devices, the measured detectivity achieved 8.7×1010 cm Hz1/2 W-1. According to additional research, the trap-assisted tunneling current is the primary component of the dark current. Controlling the trap concentration to as low as 1×1013 cm-3 will be continuous and meaningful work. The proposed study provides guidance for VLWIR HgCdTe photodetectors.

Mercury Cadmium Telluride

Abstract: Optical properties, particularly in the infrared range of wavelengths, continue to be of enormous interest to both material scientists and device engineers. The need for the development of standards for data of optical properties in the infrared range of wavelengths is very timely considering the on-going transition of nano-technology from fundamental R&D to manufacturing. The recent progress in two-dimensional materials is an example of this evolution in materials science and engineering. Radiative properties play a critical role in the processing, process control and manufacturing of semiconductor materials, devices, circuits and systems. The design and implementation of real-time, non-contact process monitoring and control methods in manufacturing, such as multi-wavelength imaging pyrometry, spectroscopic ellipsometry and reflectometry, require the knowledge of the radiative properties of materials. The design and manufacturing of sensors, imagers, waveguides, filters, antireflection coatings and lenses, operating in the infrared range of wavelengths, requires a reliable database of the radiative properties of materials. This book reviews the optical properties of various semiconductors in the infrared range of wavelengths. Some fundamental and experimental studies of the radiative properties of semiconductors are presented. Previous studies, potential applications and future developments are outlined. In chapter 1, an introduction to the radiative properties is presented. A brief overview of the optical and thermal properties is presented in chapter 2. Examples of the instrumentation for the measurements of the radiative properties are described in chapter 3. In chapters 4–13, case studies of the radiative properties of several semiconductors are elucidated. The modeling and applications of these properties are explained in chapters 14 and 15, respectively. In chapter 16, examples of the global infrastructure for these measurements are illustrated.

Plasmon-Enhanced Light Absorption in Mid-Wavelength Infrared HgCdTe Detectors

Abstract: Multiphysics modeling of a planar HgCdTe-based mid-wavelength infrared (MWIR) focal plane array with $3\,\mu$ m-wide pixels enlightens the role of surface plasmon-polaritons observed in gold nanorods arranged on its illuminated face. Simulations indicate that the proposed plasmonic detector, which employs a $1\,\mu$ m-thick absorber layer, exhibits a reduction of diffusive inter-pixel crosstalk by more than one order of magnitude with respect to more conventional, non-plasmonic detectors with a $5\,\mu$ m-thick absorber layer, without penalizing responsivity and achieving increased detectivity in the whole MWIR band by taking advantage of the absorber volume reduction.

Plasmon-Enhanced Light Absorption in Mid-Wavelength Infrared HgCdTe Detectors

Abstract: Multiphysics modeling of a planar HgCdTe-based mid-wavelength infrared (MWIR) focal plane array with $3\,\mu$ m-wide pixels enlightens the role of surface plasmon-polaritons observed in gold nanorods arranged on its illuminated face. Simulations indicate that the proposed plasmonic detector, which employs a $1\,\mu$ m-thick absorber layer, exhibits a reduction of diffusive inter-pixel crosstalk by more than one order of magnitude with respect to more conventional, non-plasmonic detectors with a $5\,\mu$ m-thick absorber layer, without penalizing responsivity and achieving increased detectivity in the whole MWIR band by taking advantage of the absorber volume reduction.