Quaternary GalnAsN containing a small amount of nitrogen (<2%) is a
potentially promising material for realizing long-wavelength emission lasers for
applications in optical communication systems. Such devices should have better high-temperature characteristics than conventional InGaAsP lasers due to an increase of the
conduction band offset. In this thesis, the GS-MBE growth of quaternary GalnAsN and
ternary GaAsN was carried out. Active N was produced by passing high purity nitrogen
gas into either an RF or an ECR plasma source. The RF plasma source was found to
produce better quality nitrides. Characterization techniques such as photoluminescence,
X-ray diffraction, TEM, SIMS, and Hall effect measurements were used to characterize
thick layers (e.g. 1 pm) and quantum wells of these nitride materials.
The concentration of N incorporated into GalnAs and GaAs is very dependent on
growth conditions and plasma conditions. The incorporation of a small amount of N into
compressively strained InGaAs reduces the strain and produces a red-shift of
photoluminescence peak. However, compared to N-free InGaAs materials, the optical
quality is dramatically degraded yielding reduced photoluminescence intensity and a
broadened FWHM of the PL peak. Hall effect measurements on un-doped, Si-doped, Bedoped thick GalnAsN layers indicate the presence of a high concentration of electron and
hole traps. The results of SIMS suggest that impurity H might be responsible for the deep
level defects formed. However, the nature of the defects is currently unknown. From
TEM observations and comparison to samples grown with a He-plasma instead of a Nplasma, spinodal decomposition and ion-induced damage in GalnAsN may produce
the reduced quality of materials, but these are not the major reasons responsible for the
dramatic degradation of optical quality.
Thermal annealing was found to be an effective method for significantly
improving the optical quality of GalnAsN with a low N concentration. Optimum
annealing conditions were obtained. Hall effect measurements on annealed samples
indicate that electron and hole traps are reduced but still present after anneal. / Thesis / Master of Engineering (ME)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/25235 |
| Date | January 2000 |
| Creators | Yuan, Lixiang |
| Contributors | Thompson, David A., Engineering Physics |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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