Correlative High-Resolution Mapping of Strain and Charge Density in a Strained Piezoelectric Multilayer
SCIE
SCOPUS
- Title
- Correlative High-Resolution Mapping of Strain and Charge Density in a Strained Piezoelectric Multilayer
- Authors
- Song, K; Koch, CT; Lee, JK; Kim, DY; KIM, JONG KYU; Parvizi, A; Jung, WY; PARK, CHAN GYUNG; Jeong, HJ; KIM, HYOUNG SEOP; Cao, Y; Yang, TN; Chen, LQ; Oh, SH
- Date Issued
- 2015-01-07
- Publisher
- WILEY-BLACKWELL
- Abstract
- A key to strain engineering of piezoelectric semiconductor devices is the quantitative assessment of the strain-charge relationship. This is particularly demanding in current InGaN/GaN-based light-emitting diode (LED) designs as piezoelectric effects are known to degrade the device performance. Using the state-of-the-art inline electron holography, we have obtained fully quantitative maps of the two-dimensional strain tensor and total charge density in conventional blue LEDs and correlated these with sub-nanometer spatial resolution. We show that the In0.15Ga0.85N quantum wells are compressively strained and elongated along the polar growth direction, exerting compressive stress/strain on the GaN quantum barriers. Interface sheet charges arising from a polarization gradient are obtained directly from the strain data and compared with the total charge density map, quantitatively verifying only 60% of the polarization charges are screened by electrons, leaving a substantial piezoelectric field in each In0.15Ga0.85N quantum well. The demonstrated capability of inline electron holography provides a technical breakthrough for future strain engineering of piezoelectric optoelectronic devices.
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/26832
- DOI
- 10.1002/ADMI.201400281
- ISSN
- 2196-7350
- Article Type
- Article
- Citation
- ADVANCED MATERIALS INTERFACES, vol. 2, no. 1, 2015-01-07
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