Local electric field measurement in GaN diodes by exciton Franz–Keldysh photocurrent spectroscopy
In: Applied Physics Letters ; volume 116, issue 20 ; ISSN 0003-6951 1077-3118, 2020
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Zugriff:
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 line shape and the local bias (Vl), uniquely determining the local electric field maximum and depletion widths. As expected, the spectrally determined values of Vl 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 (Vbi) is estimated by extrapolating Vl at V=0, which, when compared with independent C-V measurements, indicates an overall ±0.31 V accuracy of Vl. 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.
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Local electric field measurement in GaN diodes by exciton Franz–Keldysh photocurrent spectroscopy
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Autor/in / Beteiligte Person: | Verma, Darpan ; Adnan, Md Mohsinur Rahman ; Rahman, Mohammad Wahidur ; Rajan, Siddharth ; Myers, Roberto C. ; National Science Foundation ; Advanced Research Projects Agency - Energy |
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Zeitschrift: | Applied Physics Letters ; volume 116, issue 20 ; ISSN 0003-6951 1077-3118, 2020 |
Veröffentlichung: | AIP Publishing, 2020 |
Medientyp: | academicJournal |
DOI: | 10.1063/1.5144778 |
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