https://commons.ru.ac.za/vital/access/manager/Index ${session.getAttribute("locale")} 5 https://commons.ru.ac.za/vital/access/manager/Repository/vital:42197 Wed 23 Jun 2021 09:36:39 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:27074 Wed 13 Mar 2024 14:24:35 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:20443 Wed 13 Mar 2024 11:43:41 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:30776 Wed 13 Mar 2024 10:12:44 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:26443 Wed 12 May 2021 23:39:45 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:39713 Wed 12 May 2021 23:21:49 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:39802 Wed 12 May 2021 23:04:40 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:9482 Wed 12 May 2021 22:57:59 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:20437 Wed 12 May 2021 22:56:10 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:8460 Wed 12 May 2021 22:43:51 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:9838 Wed 12 May 2021 22:18:20 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:8160 Wed 12 May 2021 21:03:46 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:21125 Wed 12 May 2021 20:57:33 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:38179 Wed 12 May 2021 20:50:21 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:39408 Wed 12 May 2021 20:27:28 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:9956 Wed 12 May 2021 20:13:19 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:8530 Wed 12 May 2021 20:07:00 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:30542 Wed 12 May 2021 19:54:48 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:8267 Wed 12 May 2021 19:47:35 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:27619 Wed 12 May 2021 19:28:19 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:30802 Wed 12 May 2021 19:16:44 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:34126 Wed 12 May 2021 19:08:39 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:16130 Wed 12 May 2021 19:05:44 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:29972 Wed 12 May 2021 18:49:49 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:30640 Wed 12 May 2021 18:21:41 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:29531 Wed 12 May 2021 18:21:22 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:20457 Wed 12 May 2021 17:57:33 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:28902 Wed 12 May 2021 17:54:31 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:33180 Wed 12 May 2021 17:47:37 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:9963 Wed 12 May 2021 17:46:24 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:29866 Wed 12 May 2021 17:40:54 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:10671 Wed 12 May 2021 17:29:22 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:36665 Wed 12 May 2021 17:09:11 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:8512 Wed 12 May 2021 17:08:31 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:30799 Wed 12 May 2021 17:07:55 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:30596 Wed 12 May 2021 17:07:32 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:20357 Wed 12 May 2021 17:06:46 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:9729 Wed 12 May 2021 17:05:22 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:9717 Wed 12 May 2021 17:04:43 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:27786 Wed 12 May 2021 16:45:23 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:31978 Wed 12 May 2021 16:36:41 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:27413 Wed 12 May 2021 16:20:56 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:8161 Wed 12 May 2021 16:18:22 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:30825 Wed 12 May 2021 16:10:54 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:8196 Wed 12 May 2021 16:07:43 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:9947 Wed 12 May 2021 16:07:26 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:21324 30°C) did however increase electron transport rates. Rapid responses to hypo-osmotic shock (i.e. osmotic downshift during freshening events) by Cyanothece sp. cells also helped minimize cell rupture due to high turgor pressure. Zooplankton abundance within the St Lucia system was negatively correlated with salinity, while grazing experiments indicated that the typical estuarine zooplankton species are able to graze on Cyanothece sp. cells. Therefore, the disappearance of zooplankton at salinities above 60 must have been an important factor in the bloom persistence. Apart from the ecological factors that were at play in St Lucia during the bloom period, the persistence of the Cyanothece sp. bloom can be attributed to the robust nature of their nutrient uptake, nitrogen fixation and photosynthetic systems to maintain activity despite extreme hypersalinity levels.]]> Wed 12 May 2021 15:59:34 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:8190 Wed 12 May 2021 15:57:39 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:9325 Wed 12 May 2021 15:50:01 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:40549 Wed 12 May 2021 15:12:07 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:42050 Wed 12 May 2021 15:09:56 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:42111 Wed 12 May 2021 15:04:32 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:40553 Wed 12 May 2021 14:52:51 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:41595 Wed 12 May 2021 14:42:47 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:41363 Wed 12 May 2021 14:25:59 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:42329 Wed 12 May 2021 14:19:44 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:42167 Wed 12 May 2021 14:18:55 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:41596 Wed 12 May 2021 14:14:01 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:40524 Wed 12 May 2021 13:55:04 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:41598 150 K) a divalent acceptor is extracted with an activation energy varying between samples based on compensation in a range of 90 meV to 70 meV. Photoluminescence measurements show four peaks with recombination mechanisms linked to the native acceptor identified in literature as either the gallium antisite and/or vacant gallium site. A fifth peak observed is attributed to the longitudinal phonon of the native acceptor. InAs and InAsSb epilayer are all grown at a temperature of 600 °C and cell pressure of 600 Torr. InAs is grown at a V/III ratio of 9.5 on GaAs substrate. Photoluminescence of the InAs layer shows two distinct peaks, one of which is an extrinsic band to band recombination. The other is attributed to free electron to acceptor or a donor-acceptor pair transition. An additional weak peak is also observed which is assigned to the longitudinal phonon of the band to band. InAsSb growth was conducted under a range of V/III ratios of 4.8 to 5, with a vapour phase composition of 0.4 to 0.435. Structural analysis via X-ray diffraction showed a 6 % to 12 % solid antimony content. Photoluminescence exhibited a single broad peak for all samples, with extended band tails. Temperature and power dependant analysis of luminescence indicated a convolution of extrinsic band to tail and band to band recombinations. Hall measurements indicated the InAsSb was n-type material with an apparent measured maximum mobility at 120 K of 9.5 × 103 cm2/V.s. and a room temperature apparent mobility of 7.5 × 103 cm2/V.s. Analysis of hall results using a two-layer model calculated a true bulk mobility of the epilayer at room temperature with an increased value of 15.4 × 103 cm2/V.s. The two-layer model details the effects of the surface conduction. From photoconductivity measurements and further analysis a resultant effective lifetime, at room temperature, was found to be on same order of magnitude as that of InAs materials. Application of a single Einstein oscillator extrapolated 0 K energy gaps for two samples of solid Sb contents of 6 % and 12 %, of 354 meV and 332 meV, respectively. Finally consideration was given to the growth of aluminium containing compounds, particularly AlGaSb. Multiple phases were observed under scanning electron microscope showing growth of GaSb regions surrounded by amorphous solid aluminium and/or aluminium oxide phases. The failure of the aluminium to incorporate into the desired crystal structure is speculated to be due to impure precursor introducing oxygen into the films. Additionally, the effectiveness of the gallium precursor compared to the aluminium precursor in helping the removal of the methyl groups at the growth surface, could also promote a preference for GaSb growth.]]> Wed 12 May 2021 13:53:32 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:28893 Thu 13 May 2021 15:31:53 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:30786 Thu 13 May 2021 13:38:18 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:28455 Thu 13 May 2021 09:54:13 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:39403 Thu 13 May 2021 08:54:11 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:28483 Thu 13 May 2021 07:24:08 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:8277 Thu 13 May 2021 07:15:19 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:27906 Thu 13 May 2021 06:51:09 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:10005 Thu 13 May 2021 06:28:32 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:39714 Thu 13 May 2021 06:27:44 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:30854 Thu 13 May 2021 06:20:56 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:35489 Thu 13 May 2021 05:55:43 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:9879 Thu 13 May 2021 05:54:16 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:30585 Thu 13 May 2021 05:45:06 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:30950 Thu 13 May 2021 05:44:48 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:30581 Thu 13 May 2021 05:38:41 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:30579 Thu 13 May 2021 05:34:31 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:34276 Thu 13 May 2021 05:07:10 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:30537 B ± 0.1ᵒ and (111) ± 0.1ᵒ] using similar growth conditions yielded a higher dot density on the (100) substrate compared to the (111) substrate. This was attributed to the presence of terraces/atomic steps induced by the misorientation on the (100) substrate, which invariably gives rise to increased adsorption and an enhanced sticking coefficient of adatoms. Studies on the influence of a buffer layer on the morphology of uncapped dots showed that the shape and size of the dots are sensitive to the thickness of the buffer layer. In some case a corrugated buffer surface resulted, which introduced order in the arrangement of the dots, which formed preferentially inside the troughs. An increase in the V/III ratio from 1.0 to 3.0 was found to reduce the areal density of the QDs, while an analysis of the diameter histograms showed a narrowing of the size distribution with an increase in V/III ratio. The larger size distribution at low V/III was ascribed to the increase in indium species and the increased indium adatom migration length. This leads to increased dot density and nucleation sites, and thus triggers an increase in the conversion of tiny QDs into thermodynamically more suitable larger dots via coalescence. However, as the V/III ratio increased, the number of indium adatoms available for growth on the surface reduced, which automatically led to a decrease in the migration length of indium species which is unfavourable for the production of nucleation sites and to a decrease in dot density. Low growth rates were found to be beneficial for the growth of a high density (~5×1010cm-2) of QDs. Photoluminescence (PL) analysis of the capped samples at low temperature (~10 K), using an excitation power of 2 mW, showed a PL peak at ∼732 meV. Upon an increase in laser power to 120 mW, a blue shift of ∼ 8 meV was noticed. This emission typically persisted up to 60–70 K. An increase in the number of InSb QD-layers, was observed to cause an increase in the luminescence spectral line width and a long-wavelength shift of the PL lines, together with an enhancement in the strength of the PL emission. However, high resolution transmission electron microscopy (HRTEM) of the capped dots revealed the formation of an InGaSb quantum well-like structure, ∼10 nm thick, which was responsible for the PL signal mentioned above. The absence of QDs in the capped sample was attributed to inter-diffusion of Ga and In during the deposition of the cap layer, giving rise to a quantum well (QW) instead of the intended QDs. The presence of threading dislocations and stacking faults were also observed in the TEM micrographs of the samples containing multilayers, which can account for the fast quenching of the PL emission with increasing temperature from these samples. Theoretical simulations of the band alignment, wave functions and energy levels were in good agreement with the data collected from the PL spectra of the samples.]]> Thu 13 May 2021 04:56:31 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:20768 Thu 13 May 2021 04:42:56 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:20916 Thu 13 May 2021 04:22:29 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:28373 Thu 13 May 2021 04:09:23 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:28258 Thu 13 May 2021 03:57:46 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:9720 Thu 13 May 2021 03:36:15 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:8159 Thu 13 May 2021 03:00:26 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:26561 Thu 13 May 2021 02:47:48 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:21350 Thu 13 May 2021 02:47:05 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:27354 Thu 13 May 2021 02:47:00 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:21139 Thu 13 May 2021 02:45:40 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:28322 Thu 13 May 2021 02:36:31 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:8238 Thu 13 May 2021 01:57:29 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:16129 Thu 13 May 2021 01:24:32 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:32597 Thu 13 May 2021 01:18:57 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:30588 Thu 13 May 2021 01:18:44 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:28328 Thu 13 May 2021 01:18:27 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:27817 Thu 13 May 2021 00:51:47 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:10057 Thu 13 May 2021 00:50:25 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:9041 Thu 13 May 2021 00:38:58 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:38260 Thu 13 May 2021 00:38:50 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:30642 Thu 13 May 2021 00:17:25 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:30949 Fri 15 Mar 2024 13:00:57 SAST ]]>