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Polarization dilution in a Ga‐polar UV‐LED to reduce the influence of polarization charges
Author(s) -
Yasuda Toshiki,
Hayashi Kento,
Katsuno Syouta,
Takeuchi Tetsuya,
Kamiyama Satoshi,
Iwaya Motoaki,
Akasaki Isamu,
Amano Hiroshi
Publication year - 2015
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201431730
Subject(s) - dilution , polarization (electrochemistry) , band offset , semiconductor , materials science , voltage , optoelectronics , light emitting diode , offset (computer science) , chemistry , band gap , physics , valence band , quantum mechanics , computer science , thermodynamics , programming language
We investigated the influence of polarization charges in nitride‐based semiconductors. The influence due to polarization charges was calculated excluding the influences of the band offset. We found that the polarization charges (1 × 10 13 cm −2 ) resulted in an energy spike of more than 100 meV at the location of the charges, which is a similar value to the band offset. We then proposed the concept of polarization dilution to suppress the energy spike for better hole transport by using a graded Mg‐doped AlGaN layer in UV‐LEDs. Device simulation results indicate lower operating voltage and higher injection efficiency by using the polarization dilution. So far, our actual 350 nm LED with the polarization dilution showed lower operating voltage. These results suggested such polarization‐charge management is important in the design of the nitride semiconductors.