Local Electric Field Measurement in GaN Diodes by exciton Franz-Keldysh Photocurrent Spectroscopy

Fuente: arXiv
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Autori principali: Verma, Darpan, Adnan, Md Mohsinur Rahman, Rahman, Mohammad Wahidur, Rajan, Siddharth, Myers, Roberto C.
Natura: Preprint
Pubblicazione: 2020
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author Verma, Darpan
Adnan, Md Mohsinur Rahman
Rahman, Mohammad Wahidur
Rajan, Siddharth
Myers, Roberto C.
author_facet Verma, Darpan
Adnan, Md Mohsinur Rahman
Rahman, Mohammad Wahidur
Rajan, Siddharth
Myers, Roberto C.
contents The eXciton Franz-Keldysh (XFK) effect is observed in GaN p-n junction diodes via the spectral variation of photocurrent responsivity data that redshift and broaden with increasing reverse bias. Photocurrent spectra are quantitatively fit over a broad photon energy range to an XFK model using only a single fit parameter that determines the lineshape, the local bias ($V_{l}$), uniquely determining the local electric field maximum and depletion widths. As expected, the spectrally determined values of $V_{l}$ vary linearly with the applied bias ($V$) and reveal a large reduction in the local electric field due to electrostatic non-uniformity. The built-in bias ($V_{bi}$) is estimated by extrapolating $V_{l}$ at $V=0$, which compared with independent C-V measurements indicates an overall $\pm$0.31 V accuracy of $V_{l}$. This demonstrates sub-bandgap photocurrent spectroscopy as a local probe of electric field in wide bandgap diodes that can be used to map out regions of device breakdown (hot spots) for improving electrostatic design of high voltage devices.
format Preprint
id arxiv_https___arxiv_org_abs_2001_03583
institution arXiv
publishDate 2020
record_format arxiv
spellingShingle Local Electric Field Measurement in GaN Diodes by exciton Franz-Keldysh Photocurrent Spectroscopy
Verma, Darpan
Adnan, Md Mohsinur Rahman
Rahman, Mohammad Wahidur
Rajan, Siddharth
Myers, Roberto C.
Applied Physics
Materials Science
The eXciton Franz-Keldysh (XFK) effect is observed in GaN p-n junction diodes via the spectral variation of photocurrent responsivity data that redshift and broaden with increasing reverse bias. Photocurrent spectra are quantitatively fit over a broad photon energy range to an XFK model using only a single fit parameter that determines the lineshape, the local bias ($V_{l}$), uniquely determining the local electric field maximum and depletion widths. As expected, the spectrally determined values of $V_{l}$ vary linearly with the applied bias ($V$) and reveal a large reduction in the local electric field due to electrostatic non-uniformity. The built-in bias ($V_{bi}$) is estimated by extrapolating $V_{l}$ at $V=0$, which compared with independent C-V measurements indicates an overall $\pm$0.31 V accuracy of $V_{l}$. This demonstrates sub-bandgap photocurrent spectroscopy as a local probe of electric field in wide bandgap diodes that can be used to map out regions of device breakdown (hot spots) for improving electrostatic design of high voltage devices.
title Local Electric Field Measurement in GaN Diodes by exciton Franz-Keldysh Photocurrent Spectroscopy
topic Applied Physics
Materials Science
url https://arxiv.org/abs/2001.03583