Over the years, chemical bath deposition (CBD) is being widely used in the fabrication of Cu (In, Ga) Se��� and CdTe based solar cells and photovoltaics. Many chalcogenides have been successfully deposited by this technique and it has received a great deal of attention owing to its low temperature and low-cost nature. CdS, an important layer in heterojunction solar cells and other optoelectronic devices, has been successfully deposited by this technique, which is normally carried out as a batch process. But a major disadvantage of batch CBD is the formation of particles and also unwanted deposition generating a lot of waste and thus resulting in defective devices. In this study, we have developed a continuous flow microreactor for CBD to overcome the drawbacks of batch process. This novel microreactor setup makes use of a micromixer for efficient mixing of the reactant streams and helps in controlling the particle size and distribution before the solution impinges on the hot substrate. CdS semiconductor thin films were successfully deposited on oxidized silicon substrates using the microreactor setup and a batch reactor as well. Comparisons of nanostructured thin films were performed by various characterization techniques. The surface morphology of the deposited films, carried out by AFM, SEM and Dektak surface profiler, clearly indicated an improved film quality in case of microreactor. This setup can also be used to deposit various other compound semiconductor thin films with improved film quality and minimum waste production. / Graduation date: 2005

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Sin Wai-Chu. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references. / Abstracts in English and Chinese. / ABSTRACT --- p.i / 論文摘要 --- p.ii / ACKNOWLEDGEMENT --- p.iii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Electroplating history --- p.1 / Chapter 1.2 --- Electroplating bath --- p.7 / Chapter 1.3 --- Electroplating analytical methods --- p.8 / Chapter 1.3.1 --- Metal content and elemental impurities analysis --- p.10 / Chapter 1.3.2 --- "Metal complex, inorganic anion and cation analysis" --- p.11 / Chapter 1.3.3 --- Organic brighteners and levelers analysis --- p.12 / Chapter 1.4 --- HPLC literature review --- p.15 / Chapter 1.5 --- My research work --- p.16 / Chapter 1.6 --- References for Chapter 1 --- p.19 / Chapter Chapter 2 --- General Experimental --- p.23 / Chapter 2.1 --- The HPLC System --- p.23 / Chapter 2.2 --- The factors that affect the separation --- p.26 / Chapter 2.2.1 --- The composition of the solvent system --- p.27 / Chapter 2.2.2 --- The selection of column --- p.30 / Chapter 2.2.3 --- The most suitable analytical wavelength for UV detection --- p.34 / Chapter 2.3 --- Challenges in analyzing electroplating baths solution --- p.35 / Chapter 2.3.1 --- High metal content --- p.36 / Chapter 2.3.2 --- Strong ligand or complexing agent --- p.36 / Chapter 2.3.3 --- Interference --- p.37 / Chapter 2.3.4 --- Extreme pH --- p.37 / Chapter 2.3.5 --- Other difficulties --- p.38 / Chapter 2.3.6 --- Maintenance of HPLC instrument --- p.38 / Chapter 2.4 --- References for Chapter 2 --- p.38 / Chapter Chapter 3 --- Palladure 200 bath HPLC analysis --- p.41 / Chapter 3.1 --- Introduction --- p.41 / Chapter 3.2 --- Experimental --- p.43 / Chapter 3.3 --- Problems in the existing UV analysis for monitoring Palladure200 process --- p.45 / Chapter 3.4 --- HPLC method development for monitoring Palladure 200 process --- p.49 / Chapter 3.5 --- Analysis of aged Palladure 200 plating bath from production line --- p.55 / Chapter 3.6 --- Conclusion --- p.57 / Chapter 3.7 --- References for Chapter 3 --- p.58 / Chapter Chapter 4 --- Nickel PC3 bath HPLC analysis --- p.59 / Chapter 4.1 --- Introduction --- p.59 / Chapter 4.2 --- Experimental --- p.60 / Chapter 4.3 --- Problems in the existing Titration method for monitoring Nickel PC3 process --- p.62 / Chapter 4.4 --- HPLC method development for monitoring Nickel PC3 process --- p.63 / Chapter 4.4.1 --- Identify individual component of Nickel PC3 process --- p.63 / Chapter 4.4.2 --- Set up a calibration curve for the Nickel PC3 Additive --- p.67 / Chapter 4.4.3 --- Analysis of aged Nickel PC3 plating bath from production line --- p.68 / Chapter 4.5 --- Conclusion --- p.71 / Chapter 4.6 --- References for Chapter 4 --- p.72 / Chapter Chapter 5 --- Solderon SC bath HPLC analysis --- p.73 / Chapter 5.1 --- Introduction --- p.73 / Chapter 5.2 --- Experimental --- p.74 / Chapter 5.3 --- Instability in the existing Cyclic Voltammetric Stripping (CVS) method for monitoring Solderon SC process --- p.76 / Chapter 5.4 --- HPLC method development for monitoring Solderon SC process --- p.77 / Chapter 5.4.1 --- Identify the individual components --- p.77 / Chapter 5.4.2 --- Set up a calibration curve for the Solderon SC Primary --- p.82 / Chapter 5.4.3 --- Analysis of aged Solderon SC plating bath from production line --- p.84 / Chapter 5.5 --- Conclusion --- p.86 / Chapter 5.6 --- References for Chapter 5 --- p.86 / Chapter Chapter 6 --- Copper Gleam PPR bath HPLC analysis --- p.87 / Chapter 6.1 --- Introduction --- p.87 / Chapter 6.2 --- Experimental --- p.89 / Chapter 6.3 --- Problems in the existing Cyclic Voltammetric Stripping (CVS) method for monitoring Copper Gleam PPR process --- p.91 / Chapter 6.4 --- HPLC method development for monitoring Copper Gleam PPR process --- p.92 / Chapter 6.4.1 --- Identify Individual components and copper PPR additivein standard bath --- p.92 / Chapter 6.4.2 --- Set up a calibration curve for the Copper Gleam PPR Additive --- p.95 / Chapter 6.4.3 --- Analysis of aged Copper Gleam PPR plating bath from production line --- p.96 / Chapter 6.4.5 --- Study of H202 effect --- p.101 / Chapter 6.4.6 --- Study of air agitation effect --- p.104 / Chapter 6.4.7 --- Study of Copper anode effect --- p.105 / Chapter 6.5 --- Conclusion --- p.107 / Chapter 6.6 --- References for Chapter 6 --- p.107 / Chapter Chapter 7 --- Silverjet220 bath HPLC analysis --- p.109 / Chapter 7.1 --- Introduction --- p.109 / Chapter 7.2 --- Experimental --- p.110 / Chapter 7.3 --- HPLC method development for monitoring Silverjet 220 process --- p.112 / Chapter 7.3.1 --- Identify individual components and Silverjet 220 Additive in the plating bath --- p.112 / Chapter 7.3.2 --- Optimize the condition for HPLC analysis --- p.117 / Chapter 7.3.3 --- Analysis of aged Silverjet 220 plating bath from production line --- p.119 / Chapter 7.4 --- Conclusion --- p.122 / Chapter 7.5 --- References for Chapter 7 --- p.123 / Chapter Chapter 8 --- Conclusions and Further Studies --- p.124 / Chapter 8.1 --- Conclusions --- p.124 / Chapter 8.2 --- Further Studies --- p.126 / APPENDIX --- p.128 / The User guide for HPLC --- p.128 / HPLC System Calibration Maintenance --- p.135 / HPLC System Preventive Maintenance --- p.145

In this thesis, manufacturing of microirradiators, electrodeposition of radioactive elements such as Ni-63, and applications of these radioactive sources are discussed. Ni-63 has a half life of 100 years and a low energy beta electron of 67 keV, ideal for low dose low linear energy transfer (LET) research. The main focus of the research is on the novel Ni-63 microirradiator. It contains a small amount of total activity of radiation but a large flux, allowing the user to safely handle the microirradiator without extensive shielding. This thesis is divided into nine chapters. Properties of microirradiators and various competing radioactive sources are compared in the introduction (chapter 1). Detailed description of manufacturing Ni-63 microirradiator using the microelectrode as the starting point is outlined in chapter 2. The microelectrode is a 25 µm in diameter Pt disk sealed in a pulled 1 mm diameter borosilicate capillary tube, as a protruding wire or recessed disk microelectrode. The electrochemically active surface area of each is verified by cyclic voltammetry. Electrodeposition of nickel with a detailed description of formulation of the electrochemical bath in a cold "non-radioactive setting" was optimized by using parameters as defined by pourbaix diagrams, radioactive electroplating of Ni-63, and incorporation of safety regulations into electrodeposition. Calibration and characterization of the Ni-63 microirradiators as protruding wire and recessed disk microirradiators is presented in chapter 3. In chapters 4 through 6, applications of the Ni-63 microirradiators and wire sources are presented. Chapter 4 provides a radiobiological application of the recessed disk microirradiator and a modified flush microirradiator with osteosarcoma cancer cells. Cells were irradiated with 2000 to 1 Bq, and real time observations of DNA double strand breaks were observed. A novel benchtop detection system for the microirradiators is presented in chapter 5. Ni-63 is most commonly measured by liquid scintillation counters, which are expensive and not easily accessible within a benchtop setting. Results show liquid scintillation measurements overestimates the amount of radiation coming from the recessed disk. A novel 10 µCi Ni-63 electrochemically deposited wire acting as an ambient chemical ionization source for pharmaceutical tablets in mass spectrometry is in chapter 6. Typically, larger radioactive sources (15 mCi) of Ni-63 have been used in an ambient ionization scenario. Additionally, this is the first application of using Ni-63 to ionize in atmosphere pharmaceutical tablets, leading to a possible field portable device. In the last chapters, chapters 7 through 8, previous microirradiator experiments and future work are summarized. Chapter 7 illustrates the prototype of the electrochemically deposited microirradiator, the Te-125 microirradiator. In conjunction with Oak Ridge National Laboratory, Te-125m is a low dose x-ray emitting element determined to be the best first prototype of an electrochemically deposited microirradiator. Manufacturing, characterization, and experiments that were not successful leading to the development of the Ni-63 microirradiator are discussed. In chapter 8, future work is entailed in continuing on with this thesis project. The work presented in the thesis is concluded in chapter 9.