Laser Diodes (LD) have numerous applications for industry, military, medicine
and communications. The first visible LD was invented in 1962 by Nick Holonyak,
emitted at 710 nm (red). In 1990s, Shuji Nakamura invented the blue and green Light
Emitting Diodes (LED) and later LDs. The production of LDs emitting between 532-
632 nm has been severely lagging behind the rest of the visible spectrum. Yellow and
orange LDs are still not accessible due to the lack of successfully grown material with
high optical efficiency. AlGaInP is the quaternary compound semiconductor used to
grow green to red LEDs and red LDs. At a material composition that is supposed
to lase below 630 nm, the optical efficiency becomes low due to the oxygen-related
defects associated with high Al content. The quantum well intermixing (QWI) is a
post-growth process that is applied to laser structure to tune the wavelength of laser.
Until now, there are limited reports on successful intermixing of InGaP/InAlGaP laser
structures while maintaining the crystal quality. In this work, we introduced a novel
intermixing process that utilizes the high strain induced by the dielectric film during
annealing to initiate the intermixing. We deposited SiO2 capping by plasma-enhanced
chemical vapor deposition (PECVD) onto the InGaP/InAlGaP laser structure emitting
at 635 nm, and then annealed the structure up to 950 Celsius for different periods
of time, resulting in an astonishing 100 nm blueshift. This blueshift allowed us to
produce an unprecedented shorter wavelength orange lasers emitting at 608 nm. For
low degree of intermixing, we have noticed an increase in the intensity of the photoluminescence (PL) signal. The improvement in the PL signal was translated to a
reduction in threshold current. We implemented the technique on an LED structure
with Al-rich QWs emitting at 590 nm. Significant increase in the PL intensity (20
folds) was observed. By analyzing the improved structure, we observed reduction in
oxygen contamination. This may represent a solution to the oxygen-related defect.
The thesis opens the door for major steps forward in GaInP/AlGaInP structures for
manufacturing efficient optoelectronic devices in the green, yellow and orange visible
range.
| Identifer | oai:union.ndltd.org:kaust.edu.sa/oai:repository.kaust.edu.sa:10754/617698 |
| Date | 08 1900 |
| Creators | Al-Jabr, Ahmad |
| Contributors | Ooi, Boon S., Computer, Electrical and Mathematical Science and Engineering (CEMSE) Division, He, Jr-Hau, Li, Lain-Jong, Tan, Hoe |
| Source Sets | King Abdullah University of Science and Technology |
| Language | English |
| Detected Language | English |
| Type | Dissertation |
| Rights | 2017-08-04, At the time of archiving, the student author of this dissertation opted to temporarily restrict access to it. The full text of this dissertation became available to the public after the expiration of the embargo on 2017-08-04. |
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