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In this thesis, a home made chirp-controlled pump-probe measurement system has been developed and is used compare the time-resolved photo-reflectance measurements of GaAs:O with different fabricated condition(2.5¡Ñ10^13 ions/cm^2 (500Kev & 800Kev), 4¡Ñ10^13 ions/cm^2 (1200Kev) and 6¡Ñ10^13 ions/cm^2 (500Kev & 800Kev), 1¡Ñ10^14 ions/cm^2 (1200Kev)).The lower-dose sample were annealed at 0,350,400,450,550 and 600¢J,respectively. The higher-dose sample were annealed at 550¢J. The chirp-controlled pump-probe measurement system with temporal resolution of around 100 femtosecond and chirp parameter tuning from ¡V539 fs^2 to +663 fs^2 is demonstrated. Meanwhile, using chirp-controlled pump-probe measurement system, ultrafast dynamics of photogenerated carrier in GaAs:O in different chirp by laser pulse is characterized.

One of two project reports: The other part is designated PART B: OFF-CAMPUS PROJECT. / <p> Ion implantation is investigated as a technique to fabricate solar cells on monocrystalline silicon. The electrical properties of the implanted layer, as determined using the Hall Effect, and solar cell performance have beep studied for varying implant species (As and P), implanted dopant concentration (10^18 - 10^21 cm^-3), implanted substrate temperature (55° to 300°K} and annealing temperature (700° to 900°C). Some progress has been made toward the optimization of the various parameters. </p> / Thesis / Master of Engineering (MEngr)

<p> Ion implanted Bragg gratings integrated in rib waveguide structures were simulated, fabricated and characterized for the silicon-on-insulator (SOI) photonics platform. After selective silicon self-implantation, to an amorphizing dose of 2x10^15 ions/cm^2, the approximately 0.3 damage-induced increase in the refractive index provided the modulation mechanism necessary for the formation of a Bragg grating. The benefits of implanted Bragg gratings compared to the more widely utilized surface relief type gratings include planar surface retention, desirable for subsequent processing and wafer bonding, and a smaller depth of the index modulation, important for minimizing filtering bandwidths. To our knowledge, this is the first time ion implantation has been utilized to produce Bragg gratings integrated in an SOI rib waveguide. The benefits of using SOI for an optoelectronics platform include: cost minimization, reduced device size, and compatibility with silicon based microelectronics.</p> <p> Device performance was simulated using coupled mode theory (CMT) in conjunction with beam propagation methods (BPM), to determine transverse modal profiles for computing coupling coefficients and to determine geometric dimensions suitable to achieve adequate grating strength and single-mode operation. The Monte Carlo ion implantation simulator SUSPREM4, implementing the binary collision approximation (BCA), was used to determine the amorphous silicon grating profiles. Implanted grating devices were then fabricated into SOI having a 2.5 μm device layer and were optically characterized. For a grating length of 2100 μm and an implant energy of 60 keV, the extinction ratio of the resonant wavelength was found to be -18.11 dB and -0.87 dB for TE and TM polarizations respectively. The excess loss per unit length was measured to be 1.2 dB/mm for TE polarization and 0.6 dB/mm for TM polarization. After annealing the gratings at temperatures of up to 300 °C, used to annihilate low energy point defects responsible for absorption, it was found that the excess loss per unit length was reduced to 0.3 dB/mm for TE polarization. Compared to etched gratings with similar dimensions, it was determined that the strength of the implanted gratings was approximately 2.5 times stronger for grating lengths one third the length as result of mode-shifting due to the higher index of refraction. This is of great consequence to the miniaturization and densification of Bragg grating based devices in silicon photonics.</p> / Thesis / Master of Applied Science (MASc)

One of two project reports. Part A can be found at: http://hdl.handle.net/11375/18522 / Recent channeling-backscattering measurements of the disorder induced by heavy ion irradiation of semiconductors has indicated radiation damage far in excess of that predicted by linear transport theory. The present work extends the investigation to TEM and compares the two techniques in an annealing study of ion irradiated silicon (~ 80-200 a.m.u. ions of 15-100 keV) for low fluence (typically 3×10¹¹/cm² for TEM and 10¹²-10¹³/cm² for channeling) bombardment. In addition to showing a good correlation between the techniques, the results indicate that neither does there exist a unique relationship between lattice disordering and cascade energy density, nor that a well defined amorphous structure seems to exist. / Thesis / Master of Engineering (ME)