Introduction

Selberherr, S.

doi:10.1007/978-3-7091-8752-4_1

Cited by 7 publications

(3 citation statements)

References 61 publications

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“…A drift-diffusion model is used to simulate the metal–semiconductor junction for each core–shell nanoparticle design through the Automat FOR Simulation of HETerostructures (AFORS-HET) software v.2.5. This numerical simulation software uses a 1D drift-diffusion model based on self-consistent solutions to the Poisson equation to model the band bending, carrier tunneling, and junction properties . See Supporting Information for input parameters and the built-in field calculation.…”

Section: Methodsmentioning

confidence: 99%

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Determining Quasi-Equilibrium Electron and Hole Distributions of Plasmonic Photocatalysts Using Photomodulated X-ray Absorption Spectroscopy

Palmer,

Lee,

Dong

et al. 2024

ACS Nano

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Most photocatalytic and photovoltaic devices operate under broadband, constant illumination. Electron and hole dynamics in these devices, however, are usually measured by using ultrafast pulsed lasers in a narrow wavelength range. In this work, we use excited-state X-ray theory originally developed for transient X-ray experiments to study steady-state photomodulated X-ray spectra. We use this method to attempt to extract electron and hole distributions from spectra collected at a nontime-resolved synchrotron beamline. A set of plasmonic metal core−shell nanoparticles is designed as the control experiment because they can systematically isolate photothermal, hot electron, and thermalized electron−hole pairs in a TiO 2 shell. Steady-state changes in the Ti L 2,3 edge are measured with and without continuous-wave illumination of the nanoparticle's localized surface plasmon resonance. The results suggest that within error the quasi-equilibrium carrier distribution can be determined even from relatively noisy data with mixed excited-state phenomena. Just as importantly, the theoretical analysis of noisy data is used to provide guidelines for the beamline development of photomodulated steady-state spectroscopy.

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Section: Methodsmentioning

confidence: 99%

“…This numerical simulation software uses a 1D drift-diffusion model based on self-consistent solutions to the Poisson equation to model the band bending, carrier tunneling, and junction properties. 55 See Supporting Information for input parameters and the built-in field calculation.…”

Section: Methodsmentioning

confidence: 99%

Determining Quasi-Equilibrium Electron and Hole Distributions of Plasmonic Photocatalysts Using Photomodulated X-ray Absorption Spectroscopy

Palmer,

Lee,

Dong

et al. 2024

ACS Nano

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“…To enhance the analysis of the SPV measurements by KPFM under illumination, we conducted band structure simulations using a one-dimensional drift-diffusion model . This model incorporates factors such as Shockley–Read–Hall (SRH), radiative and Auger recombinations, laser excitation, and polarization charges.…”

Section: Experimental Methodsmentioning

confidence: 99%

GaN/InGaN LED Sidewall Defects Analysis by Cathodoluminescence and Photosensitive Kelvin Probe Force Microscopy

González-Izquierdo,

Rochat,

Sakowski

et al. 2024

ACS Photonics

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This paper delves into the impact of sidewall defects on a GaN/ InGaN epi-LED, utilizing advanced analytical techniques with nanometric resolution: cathodoluminescence (CL) and photosensitive Kelvin probe force microscopy (KPFM). CL investigations at varying excitation energies enable an indepth study of the epi-LED by distinctly probing the top p-GaN layer and InGaN quantum wells within the mesa structure. These measurements permit the analysis of the impact of sidewall defects on the light-emitting diode (LED) light emission in different epilayers, shedding light on the phenomena affecting LED optoelectronic properties. The results reveal reduced intensities related to the GaN near-band-edge (NBE) and InGaN quantum well emission, along with an increased yellow luminescence band near the mesa edge, attributed to sidewall defects induced during the etching process. Conversely, the top p-GaN layer shows no NBE band and uniform ultraviolet luminescence line (UVL) related to Mg Ga acceptors, suggesting no effect from sidewall defects. Similarly, the surface photovoltage (SPV) measured on the top p-GaN surface by KPFM shows no significant changes near the mesa boundary. Moreover, KPFM measurements show a slow SPV decay after illumination, indicating charge trapping of holes in the surface of p-GaN, as evidenced by positive SPV and consistent with the simulations. We attribute the absence of the sidewall defects effect and the charge trapping in the p-GaN layer to high-density Mg-related defects, as supported by the uniform CL UVL emission. To ensure that sidewall defects were not masked by the high concentration of Mg impurities, we conducted photosensitive KPFM at low temperatures. At these temperatures, defects are "frozen", and different types of defects exhibit distinct detrapping time scales. The consistent behavior observed at both the center and border of the mesa structure across three different temperatures confirms that only one type of defect associated with Mg doping rather than sidewall defects is being observed. These findings suggest that the etching process used in LED fabrication does not significantly impact the role of the top p-GaN layer in LED miniaturization. Moreover, they provide crucial insights into defect-induced processes and their influence on device performance, particularly in the vicinity of LED edges. Understanding these effects is essential for fabricating high-performance microLEDs.

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New explicit current/voltage equation forp-i-nsolar cells including interface potential drops and drift/diffusion transport

Taretto

2012

Prog. Photovolt: Res. Appl.

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Analytical modeling of p-i-n solar cells constitutes a practical tool to extract electronic material and device parameters from fits to experimental data and to establish optimization criteria. This paper proposes a model for p-i-n solar cells based on a new approximation, which estimates the electric field taking into account interface potential drops at the intrinsic-to-doped interfaces. This leads to a closed-form current/voltage equation that shows very good agreement with device simulations, revealing that the inclusion of the interface potential drops constitutes a major correction to the classical uniform-field approach. Furthermore, the model is able to fit experimental current/voltage curves of efficient nanocrystalline Si and microcrystalline Si p-i-n solar cells under illumination and in the dark, obtaining material parameters such as mobility-lifetime product, built-in voltage, or surface recombination velocity.

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Introduction

Cited by 7 publications

References 61 publications

Determining Quasi-Equilibrium Electron and Hole Distributions of Plasmonic Photocatalysts Using Photomodulated X-ray Absorption Spectroscopy

Determining Quasi-Equilibrium Electron and Hole Distributions of Plasmonic Photocatalysts Using Photomodulated X-ray Absorption Spectroscopy

GaN/InGaN LED Sidewall Defects Analysis by Cathodoluminescence and Photosensitive Kelvin Probe Force Microscopy

New explicit current/voltage equation forp-i-nsolar cells including interface potential drops and drift/diffusion transport

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