Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5489463 | Journal of Crystal Growth | 2017 | 13 Pages |
Abstract
P-down LEDs (PDLEDs) have the potential to open up new design schemes for III-nitride LEDs compared to conventional n-down LEDs (NDLEDs). For light emitters operating above 480Â nm, the PDLED design enables the epitaxial advantages of semipolar (202Ì
1) and gains the polarization benefits of semipolar (202Ì
1Ì
). Here, we investigated semipolar (202Ì
1) InGaN-based PDLEDs in terms of their photoluminescence (PL) spectra and compositional profile. Despite concerns of the Mg memory effect degrading PDLED performance due to Mg-related non-radiative recombination centers, the PL intensities were nearly identical between the NDLED and PDLEDs, which emitted at wavelengths centered near 500 nm. Secondary ion mass spectrometry revealed that the Mg doping levels in the multiple quantum well (MQW) active region were comparable for each structure, with average values of 2.9Ã1018 cmâ3 for the NDLED and 1.8Ã1018 cmâ3 for the PDLED. Prior to growing the active region MQW, a 700 °C in situ anneal was carried out to reduce the average Mg concentration in the PDLED MQW to 3.7Ã1017 cmâ3. Its hydrogen concentration remained at 5Ã1019 cmâ3 in the p-type GaN region, which suggests that hydrogen passivation occurs during the growth of subsequent epitaxial layers in ammonia.
Keywords
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
C. Forman, J. Leonard, B. Yonkee, C. Pynn, T. Mates, D. Cohen, R. Farrell, T. Margalith, S. DenBaars, J. Speck, S. Nakamura,