https://vital.seals.ac.za/vital/access/manager/Index ${session.getAttribute("locale")} 5 https://vital.seals.ac.za/vital/access/manager/Repository/vital:30807 Wed 17 Jan 2024 13:06:29 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:32483 Wed 13 Mar 2024 11:50:54 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:30809 Wed 13 Mar 2024 10:54:08 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:32357 Wed 13 Mar 2024 10:12:28 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:41606 Wed 13 Mar 2024 09:37:38 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:36580 Wed 13 Mar 2024 09:30:27 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:36483 Wed 12 May 2021 23:23:16 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:28543 Wed 12 May 2021 23:16:16 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:38190 Wed 12 May 2021 23:13:45 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:33920 Wed 12 May 2021 23:03:58 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:39482 Wed 12 May 2021 22:33:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:39810 Wed 12 May 2021 22:29:37 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:37038 Wed 12 May 2021 22:27:35 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:38179 Wed 12 May 2021 20:50:21 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:38191 Wed 12 May 2021 20:50:17 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:39408 Wed 12 May 2021 20:27:28 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:38335 Wed 12 May 2021 20:07:20 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:31828 Wed 12 May 2021 20:00:19 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:30542 Wed 12 May 2021 19:54:48 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:29479 Wed 12 May 2021 19:46:14 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:33385 Wed 12 May 2021 19:31:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:28477 Wed 12 May 2021 19:31:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:30802 Wed 12 May 2021 19:16:44 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:34126 Wed 12 May 2021 19:08:39 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:30468 Wed 12 May 2021 18:25:47 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:36239 Wed 12 May 2021 18:11:36 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:38189 Wed 12 May 2021 18:05:20 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:28902 Wed 12 May 2021 17:54:31 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:33029 10 and TPI between -1 and 1. Landslides are less pronounced on slope zones where slope gradient is <15˚ and >45˚, profile curvature <0, TWI <8 and >18, SPI <10 and TPI >1. Deep soil profiles ranging between 2.5 and 7 meters are a major characteristic of the study area. Soils are characterized by clay pans at a depth ranging between 0.75 and 3 meters within the profiles. The study area is dominated by clay texture, except for the uppermost surface horizons, which are loamy sand. All surface horizons analysed had the percentage of sand, silt and clay ranging from 33 to 55%, 22 to 40% and 10 to 30% respectively. In the deeper horizons, sand was observed to reduce drastically to less than 23%, while clay increased to greater than 50%. The clay content is very high in the deeper horizons exceeding 35%. By implication, such soils with a very high clay content and plasticity index are considered as Vertisols, with a profound influence in the occurrence of landslides. The top soil predominantly contains more quartz, while subsurface horizons have considerable amounts of illite/muscovite as the dominant clay minerals, ranging from 43% to 47 %. The liquid limit, plasticity index, computed weighted plasticity index (PIw), expansiveness (ɛex) and dispersion ranging from 50, 22, 17, 10 and 23 to 66, 44,34,54 and 64, respectively also have strong implications for landslide occurrence. Landslides are not normally experienced during or immediately after extreme rainfall events but occur later in the rainfall season. By implication, this time lag in landslide occurrence and rainfall distribution, is due to the initial infiltration through quartz dominated upper soil layers, before illite/muscovite clays in the lower soil horizons get saturated. Whereas forest cover reduced from 40 % in 1985 to 8% in 2015, cultivated land and settlements increased from 16% and 11% to 52% and 25% respectively during the same period. The distribution of cultivated land decreased in lower slope sections within gradient group < 15˚ by 59%. It however increased in upper sections within gradient cluster 25˚ to 35˚ by over 85% during the study period. There is a shift of cultivated land to the steeper sensitive upper slope elements associated with landslides in the study area. More than 50% of the landslides are occurring on cultivated land, 20% on settlements while less than 15 % and 10% are occurring on grassland and forests with degraded areas respectively. Landslides in Kigezi highlands are triggered by a complex interaction of multiple- factors, including dynamic triggers and ground condition variables. Topographic hollows are convergence zones within the landscape where all the parameters interact to cause landslides. Topographic hollows are therefore potential and actual landslide sites in the study area. Characterized by deep soil horizons with high clay content dominated by illite/muscovite minerals in the sub soils and profile concave forms with moderately steep slopes, topographic hollows are the most vulnerable slope elements to landslide occurrence. The spatial temporal patterns of landslide occurrence in the study area has changed due to increased cultivation of steep middle and upper slopes. Characterized by deep soil horizons with high clay content dominated by illite/muscovite minerals in the sub soils and profile concave forms with moderately steep slopes, topographic hollows are the most vulnerable slope elements to landslide occurrence. The spatial-temporal patterns of landslide occurrence in the study area has changed due to increased cultivation of steep middle and upper slopes. A close spatial and temporal correlation between land use/cover changes and landslide occurrence is discernible. The understanding of these topographical, pedological and land use/cover parameters and their influence on landslide occurrence is important in land management. It is now possible to identify and predict actual and potential landslide zones, and also demarcate safer zones for community activities. The information generated about the area’s topographic, pedological and land cover characteristics should help in vulnerability mitigation and enhance community resilience to landslide hazards in this fragile highland ecosystem. This can be done through designating zones for community activities while avoiding potential landslide zones. It is also recommended that, tree cover restoration be done in the highlands and the farmers encouraged to re-establish terrace farming while avoiding cultivation of sensitive steep middle and upper slope sections.]]> Wed 12 May 2021 17:50:51 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:31333 Wed 12 May 2021 17:50:28 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:28353 Wed 12 May 2021 17:41:57 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:37050 Wed 12 May 2021 17:31:57 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:39509 Wed 12 May 2021 17:20:28 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:37047 Wed 12 May 2021 17:17:09 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:36921 Wed 12 May 2021 17:12:16 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:28764 Wed 12 May 2021 16:53:01 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:30948 Wed 12 May 2021 16:47:38 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:37164 Wed 12 May 2021 16:42:14 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:32479 Wed 12 May 2021 16:31:53 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:36666 Wed 12 May 2021 16:27:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:37158 Wed 12 May 2021 16:08:02 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:41618 Wed 12 May 2021 15:10:54 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:42050 Wed 12 May 2021 15:09:56 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:41620 Wed 12 May 2021 15:05:32 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:42111 Wed 12 May 2021 15:04:32 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:41595 Wed 12 May 2021 14:42:47 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:41605 Wed 12 May 2021 14:32:55 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:42873 Wed 12 May 2021 14:32:43 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:42329 Wed 12 May 2021 14:19:44 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:42167 Wed 12 May 2021 14:18:55 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:41615 Wed 12 May 2021 14:17:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:41596 Wed 12 May 2021 14:14:01 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:42048 Wed 12 May 2021 13:59:14 SAST ]]> https://vital.seals.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://vital.seals.ac.za/vital/access/manager/Repository/vital:30786 Thu 13 May 2021 13:38:18 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:36926 Thu 13 May 2021 12:45:50 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:28455 Thu 13 May 2021 09:54:13 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:39403 Thu 13 May 2021 08:54:11 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:32513 Thu 13 May 2021 08:52:29 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:37048 Thu 13 May 2021 08:47:30 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:32396 80 mm) showed a greater component of invertebrates in previously unexplored habitats, which proves their omnivorous diet related to ontogenetic niche use. Knowledge of fine-scale habitat use by fishes is essential for conservation planning as exclusion zones can be optimised to limit anthropogenic influence on nursery use patterns in fishes. The availability of shallow water habitats (<60 cm) was assessed as an additional driver to explain the species diversity and richness of juvenile fishes within the lower reaches. These habitats are known as important nursery habitats providing numerous marine and estuarine spawned fishes with adequate refuge and food supply. This shallow water volume was measured by means of a two-man kayak using both the spring high and low tides in the lower reaches of these systems to assess juvenile assemblages. It was clear from the results that aquatic vegetation significantly adds to the volume of these areas and as a result, much greater fish density and species richness were observed. Generalized additive models showed that marine spawned species were particularly reliant on the availability of this shallow water along with submerged vegetation and additional environmental variables. The presence of structurally submerged vegetation typically characterized within shallow estuarine waters is commonly believed to reduce predation risk resulting in elevated densities of biota. Based on the current stock status and percentage of pristine breeding stock, five fish species classified as collapsed/overexploited was consistently found within these systems with an additional 14 species currently classified as exploited/vulnerable. Based on the current species richness and diversity, available habitat cover and knowledge regarding important recreational species, priority areas that require some form of legal protection in order to meet potential biodiversity targets, could be identified. It is a legal requirement in South Africa that all estuaries require management plans that should be based on good knowledge of priority habitats for fauna and flora. The identification of estuarine protected areas is seen as a mechanism for protecting a representative sample of the biodiversity accompanied by a complete range of environmental gradients and habitat types at a reasonable scale in order to maximize the protection of estuarine species.]]> Thu 13 May 2021 08:20:19 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:36664 NSN2 (148.55 mg/g) > NNN1 (131.88 mg/g) > NNN2 (75.87 mg/g). The bis-benzimidazole derivatives preference for metal ions was further investigated with a multi-element solution containing Rh(III), Ir(III), Pt(II), Pd(II) and Ni(II). The bis-benzimidazole derivatives showed the following order of loading capacity: NSN1 (47.28 mg/g) > NSN2 (23.89 mg/g) > NNN1 (17.47 mg/g) > NNN2 (14.91 mg/g) for Rh(III); NSN2 (10.64 mg/g) > NNN2 (6.84 mg/g) > NSN1 (5.74 mg/g) > NNN1 (5.02 mg/g) for Ir(III); NNN2 (33.96 mg/g) > NSN1 (30.95 mg/g) > NSN2 (19.95 mg/g) > NNN1 (14.92 mg/g) for Pt(II); NNN1 (47.94 mg/g) > NNN2 (28.90 mg/g) > NSN1 (16.22 mg/g) > NSN2 (15.83 mg/g) for Pd(II). Bis-benzimidazole derivatives showed no uptake of nickel(II) under these conditions. It was observed the ligand-selectivity order for Rh(III) was similar in both single-element and multi-element studies. This order showed that the bis-benzimidazoles containing a sulfur atom showed a high preference for rhodium(III) compared to Pt(II) which had a high preference for NNN2 as well as Pd(II) which had a high preference for NNN1. Ir(III) generally had a lower preference for the ligands presumably due to its higher kinetic inertness compared with Rh(III). Column sorption of [IrCl6]2- and [RhCl5(H2O)]2- on nanofibers functionalized with diammonium cations was carried out and the loading capacities of [IrCl6]2- were obtained. [RhCl5(H2O)]2- was not adsorbed by the sorbent materials while [IrCl6]2- was loaded onto the column. The loading capacities of [IrCl6]2- with the quaternary diammonium sorbent materials increased in the order of F-QuatDMDAMeBnz (60.29 mg/g) < F-QuatDMDABnz (67.61 mg/g) < F-QuatDMDACF3Bnz (107.59 mg/g) < F-QuatDMDANO2Bnz (140.47 mg/g). The loading capacity for Ir(IV) with quaternary diammonium cationic nanofibers increased with an increase in the electron-withdrawing nature of the quaternizing group. The charge delocalizing ability of the nitrobenzyl group resulted in the best interaction of the diammonium cation with [IrCl6]2-. Batch equilibrium studies were carried out to assess the efficiency of bis-benzimidazole chelating derivatives as adsorbents using a multi-metal solution (Rh(III), Ir(III), Pt(II), Pd(II) and Ni(II)) in 0.5 M HCl. The efficiency of the quaternary diammonium cations was tested using a binary metal solution (Ir(IV) and Rh(III)) in 6 M HCl. The isothermal batch adsorption studies of a multi-metal solution with bis-benzimidazoles derivatives fitted the Langmuir isotherm model which confirmed monolayer adsorption onto a homogeneous surface. The Langmuir isotherm parameter (qe (mg/g)), using functionalized nanofibers, showed the order of NNN2 (128.21 mg/g) > NSN1 (99.01 mg/g) > NSN2 (91.74 mg/g) > NNN1 (84.03 mg/g) for Pt(II); NNN1 (66.23 mg/g) > NNN2 (5.89 mg/g) > NSN1 (1.40 mg/g) > NSN2 (0.59 mg/g) for Pd(II); NSN2 (10.64 mg/g) > NNN2 (6.84 mg/g) > NSN1 (5.74 mg/g) > NNN1 (5.02 mg/g) for Ir(III); NSN1 (140.85 mg/g) > NSN2 (109.89 mg/g) > NNN1 (104.17 mg/g) > NNN2 (91.74 mg/g) for Rh(III). The pseudo-first-order kinetics model was found to be the best fit to describe the adsorption kinetics of all metal ions onto all the sorbent materials. K1 (min-1) value in pseudo-first-order kinetics showed the same order of adsorption as observed in the Langmuir isotherms. The isothermal batch adsorption studies of [IrCl6]2- and [RhCl5(H2O)]2- with quaternary diammonium cations fitted the Freundlich isotherm model and confirmed to be effective for multiple-layered adsorption onto a heterogeneous surface. The Freundlich isotherm parameter (kf (mg/g)) using functionalized quaternary diammonium cationic nanofibers increased in the order of F-QuatDMDANO2Bnz (794.33 mg/g) > F-QuatDMDACF3Bnz (185.35 mg/g) > F-QuatDMDABnz (156.32 mg/g) > F-QuatDMDAMeBnz (112.46 mg/g) for Ir(IV) uptake. F-QuatDMDANO2Bnz resin showed the highest adsorption than that of F-QuatDMDAMeBnz, F-QuatDMDABnz and F-QuatDMDACF3Bnz and this order is similar to what was observed in column studies. The quaternary diammonium cations were shown to have the highest adsorption capacity for Ir(IV) compared with Rh(III). The adsorption of Rh(III) was also observed to increase in the order of F-QuatDMDANO2Bnz (177.83 mg/g) > F-QuatDMDACF3Bnz (40.37 mg/g) > F-QuatDMDABnz (36.98 mg/g) > F-QuatDMDAMeBnz (12.71 mg/g). The pseudo-second-order kinetic model was found to be the best fit to describe the adsorption kinetics of both metal ions onto all the sorbent materials. K2 (g.mg-1min-1) value in pseudo-second-order kinetics showed the same order of adsorption as observed in the Freundlich isotherms. The adsorption studies showed adsorption takes place via chemisorption process. This thesis presents PGMs and iridium-specific materials that could be applied in solutions of secondary PGMs sources containing rhodium, platinum and palladium with bis-benzimidazoles as well as in feed solutions from ore processing with diammonium cations for iridium recovery.]]> Thu 13 May 2021 07:20:28 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:36501 Thu 13 May 2021 07:19:19 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:30432 Thu 13 May 2021 06:47:35 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:32266 Thu 13 May 2021 06:46:04 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:39514 Thu 13 May 2021 06:28:25 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:35489 Thu 13 May 2021 05:55:43 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:36140 Thu 13 May 2021 05:47:12 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:30950 Thu 13 May 2021 05:44:48 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:32669 Thu 13 May 2021 05:24:44 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:31640 Thu 13 May 2021 05:23:01 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:33442 Thu 13 May 2021 05:11:34 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:34276 Thu 13 May 2021 05:07:10 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:33379 Thu 13 May 2021 05:00:45 SAST ]]> https://vital.seals.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://vital.seals.ac.za/vital/access/manager/Repository/vital:38259 Thu 13 May 2021 04:33:34 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:35756 Thu 13 May 2021 04:25:22 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:33941 Thu 13 May 2021 04:07:46 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:30944 Thu 13 May 2021 03:58:25 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:29989 Thu 13 May 2021 03:41:22 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:36155 Thu 13 May 2021 02:25:13 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:31235 Thu 13 May 2021 02:19:18 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:27431 Thu 13 May 2021 02:14:13 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:36629 Thu 13 May 2021 01:56:47 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:30826 Thu 13 May 2021 01:54:40 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:39811 Thu 13 May 2021 01:49:35 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:36590 Thu 13 May 2021 01:43:19 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:27416 Thu 13 May 2021 01:33:39 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:36791 Thu 13 May 2021 01:32:02 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:30087 Thu 13 May 2021 01:29:01 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:30588 Thu 13 May 2021 01:18:44 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:31128 Thu 13 May 2021 01:09:19 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:33609 Thu 13 May 2021 00:55:08 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:36574 Thu 13 May 2021 00:50:46 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:38260 Thu 13 May 2021 00:38:50 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:28943 Thu 13 May 2021 00:38:28 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:34047 Thu 13 May 2021 00:29:28 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:30958 Thu 13 May 2021 00:22:00 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:30642 Thu 13 May 2021 00:17:25 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:30949 Fri 15 Mar 2024 13:00:57 SAST ]]>