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Previous Raman measurements on supported graphene under high pressure reported a very different shift rate of in-plane phonon frequency of graphene (16 cm$^{-1}$GPa$^{-1}$) from graphite (4.7 cm$^{-1}$GPa$^{-1}$), implying very different in-plane anharmonicity that graphene gets stiffer than graphite in-plane under the same pressure. It was suggested that it could be due to the adhesion of graphene to substrates. We have therefore performed high pressure Raman measurements on unsupported graphene and we find a similar in-plane stiffness and anharmonicity of graphene (5.4 cm$^{-1}$GPa$^{-1}$) to graphite. On the other hand, the out-of-plane stiffness of graphene is hard to define, due to the 2D nature of graphene. However, we estimate a similar out-of-plane stiffness of graphene (1.4$\pm$295 GPa) to that of graphite (38.7$\pm$7 GPa), by measuring its effect on the shift of the in-plane phonon frequency with pressure., Comment: 5 pages, 5 figures

Background: Previous studies have reported national and regional Global Burden of Disease (GBD) estimates for the UK. Because of substantial variation in health within the UK, action to improve it requires comparable estimates of disease burden and risks at country and local levels. The slowdown in the rate of improvement in life expectancy requires further investigation. We use GBD 2016 data on mortality, causes of death, and disability to analyse the burden of disease in the countries of the UK and within local authorities in England by deprivation quintile. Methods: We extracted data from the GBD 2016 to estimate years of life lost (YLLs), years lived with disability (YLDs), disability-adjusted life-years (DALYs), and attributable risks from 1990 to 2016 for England, Scotland, Wales, Northern Ireland, the UK, and 150 English Upper-Tier Local Authorities. We estimated the burden of disease by cause of death, condition, year, and sex. We analysed the association between burden of disease and socioeconomic deprivation using the Index of Multiple Deprivation. We present results for all 264 GBD causes of death combined and the leading 20 specific causes, and all 84 GBD risks or risk clusters combined and 17 specific risks or risk clusters. Findings: The leading causes of age-adjusted YLLs in all UK countries in 2016 were ischaemic heart disease, lung cancers, cerebrovascular disease, and chronic obstructive pulmonary disease. Age-standardised rates of YLLs for all causes varied by two times between local areas in England according to levels of socioeconomic deprivation (from 14 274 per 100 000 population [95% uncertainty interval 12 791–15 875] in Blackpool to 6888 [6145–7739] in Wokingham). Some Upper-Tier Local Authorities, particularly those in London, did better than expected for their level of deprivation. Allowing for differences in age structure, more deprived Upper-Tier Local Authorities had higher attributable YLLs for most major risk factors in the GBD. The population attributable fractions for all-cause YLLs for individual major risk factors varied across Upper-Tier Local Authorities. Life expectancy and YLLs have improved more slowly since 2010 in all UK countries compared with 1990–2010. In nine of 150 Upper-Tier Local Authorities, YLLs increased after 2010. For attributable YLLs, the rate of improvement slowed most substantially for cardiovascular disease and breast, colorectal, and lung cancers, and showed little change for Alzheimer's disease and other dementias. Morbidity makes an increasing contribution to overall burden in the UK compared with mortality. The age-standardised UK DALY rate for low back and neck pain (1795 [1258–2356]) was higher than for ischaemic heart disease (1200 [1155–1246]) or lung cancer (660 [642–679]). The leading causes of ill health (measured through YLDs) in the UK in 2016 were low back and neck pain, skin and subcutaneous diseases, migraine, depressive disorders, and sense organ disease. Age-standardised YLD rates varied much less than equivalent YLL rates across the UK, which reflects the relative scarcity of local data on causes of ill health. Interpretation: These estimates at local, regional, and national level will allow policy makers to match resources and priorities to levels of burden and risk factors. Improvement in YLLs and life expectancy slowed notably after 2010, particularly in cardiovascular disease and cancer, and targeted actions are needed if the rate of improvement is to recover. A targeted policy response is also required to address the increasing proportion of burden due to morbidity, such as musculoskeletal problems and depression. Improving the quality and completeness of available data on these causes is an essential component of this response. Funding: Bill & Melinda Gates Foundation and Public Health England.

The impact of the stress in room temperature inductively coupled plasma chemical vapour deposited (ICP-CVD) SiN x surface passivation layers on off-state drain ( I DS-off) and gate leakage currents ( I GS) in AlGaN/GaN high electron mobility transistors (HEMTs) is reported. I DS-off and I GS in 2 μm gate length devices were reduced by up to four orders of magnitude to ∼10 pA/mm using a compressively stressed bilayer SiN x passivation scheme. In addition, I on/ I off of ∼10 11 and subthreshold slope of 68 mV/dec were obtained using this strain engineered surface passivation approach.

In this paper we demonstrate a THz microstrip stack antenna on GaN-on-low resistivity silicon substrates (ρ < 40 Ω.cm). To reduce losses caused by the substrate and to enhance performance of the integrated antenna at THz frequencies, the driven patch is shielded by silicon nitride and gold in addition to a layer of benzocyclobutene (BCB). A second circular patch is elevated in air using gold posts, making this design a stack configuration. The demonstrated antenna shows a measured resonance frequency in agreement with the modeling at 0.27 THz and a measured S11 as low as −18 dB was obtained. A directivity, gain and radiation efficiency of 8.3 dB, 3.4 dB, and 32% respectively was exhibited from the 3D EM model. To the authors' knowledge, this is the first demonstrated THz integrated microstrip stack antenna for TMIC (THz Monolithic Integrated Circuits) technology; the developed technology is suitable for high performance III-V material on low resistivity/high dielectric substrates.

Controlling the long-range homogeneity of core-shell InGaN/GaN layers is essential for their use in light-emitting devices. This paper demonstrates variations in optical emission energy as low as ~7 meV.µm-1 along the m-plane facets from core-shell InGaN/GaN single quantum wells as measured through high-resolution cathodoluminescence hyperspectral imaging. The layers were grown by metal organic vapor phase epitaxy on etched GaN nanorod arrays with a pitch of 2 µm. High-resolution transmission electron microscopy and spatially-resolved energy-dispersive X-ray spectroscopy measurements demonstrate a long-range InN-content and thickness homogeneity along the entire 1.2 μm length of the m-plane. Such homogeneous emission was found on the m-plane despite the observation of short range compositional fluctuations in the InGaN single quantum well. The ability to achieve this uniform optical emission from InGaN/GaN core-shell layers is critical to enable them to compete with and replace conventional planar light-emitting devices.

The African Very Long Baseline Interferometry Network (AVN) is a pan-African project that will develop Very Long Baseline Interferometry (VLBI) observing capability in several countries across the African continent, either by conversion of existing telecommunications antennas into radio telescopes, or by building new ones. This paper focuses on the conversion of the Nkutunse satellite communication station (near Accra, Ghana), specifically the early mechanical and infrastructure upgrades, together with the development of a custom ambient receiver and digital backend. The paper concludes with what remains to be done, before the station can be commissioned as an operational VLBI station., Comment: Submitted and accepted by IEEE EuCap. Not presented and therefore not published in conference proceedings

We benchmarked growth, microstructure and photo luminescence (PL) of (11$\bar 2$2) InGaN quantum wells (QWs) against (0001) and (11$\bar 2$0). In incorporation, growth rate and the critical thickness of (11$\bar 2$2) QWs are slightly lower than (0001) QWs, while the In incorporation on (11$\bar 2$0) is reduced by a factor of three. A small step-bunching causes slight fluctuations of the emission wavelength. Transmission electron microscopy as well as atom probe tomography (APT) found very flat interfaces with little In segregation even for 20% In content. APT frequency distribution analysis revealed some deviation from a random InGaN alloy, but not as severe as for (11$\bar 2$0). The slight deviation of (11$\bar 2$2) QWs from an ideal random alloy did not broaden the 300 K PL, the line widths were similar for (11$\bar 2$2) and (0001) while (11$\bar 2$0) QWs were broader. Despite the high structural quality and narrow PL, the integrated PL signal at 300 K was about 4$\times$ lower on (11$\bar 2$2) and more than 10$\times$ lower on (11$\bar 2$0).

The microstructure of semi-polar (1 1 2 2) GaN templates grown on pre-structured r-plane sapphire by metal–organic vapor phase epitaxy (MOVPE) followed by hydride vapor phase epitaxy (HVPE) has been characterised by transmission electron microscopy (TEM). It is found that dislocations originating from the inclined c-plane-like GaN/sapphire interface bend and then terminate either at the coalescence regions of the adjacent GaN stripes or at the SiO2 mask. However, the regions associated with the coalescence event during the MOVPE growth act as a source of dislocations and stacking faults in the subsequent growth process. More importantly, a direct link between the formation of a surface hillock, the presence of an inversion domain, and the preferential nucleation of randomly oriented GaN particles at a region containing a dislocation bundle originating from coalescence has been established. It is suggested that controlling the surface conditions of the MOVPE GaN layer before HVPE and optimising the HVPE nucleation process are important to avoid the surface hillocks.

High resolution transmission electron microscopy has been employed to investigate the impact of the GaN bar-rier growth technique on the composition profile of InGaN quantum wells (QWs). We show that the profiles deviate from their nominal configuration due to the pres-ence of an indium tail at the upper interface of the QW. This indium tail, thought to be associated with a segrega-tion effect from the indium surfactant layer, has been shown to strongly depend on the growth method. The ef-fect of this tail has been investigated using a self-consistent Schrödinger-Poisson simulation. For the simu-lated conditions, a graded upper interface has been found to result in a decreased electron-hole wavefunction over-lap of up to 31 % compared to a QW with a rectangular profile, possibly leading to a decrease in radiative-recombination rate. Therefore in order to maximize the efficiency of a QW structure, it is important to grow the active region using a growth method which leads to QW interfaces which are as abrupt as possible. The results of this experiment find applications in every study where the emission properties of a device are correlated to a particular active region design.

The impact of the miscut of a (0001) c-plane substrate on the structural and optical properties of InGaN/GaN quantum wells grown by metal-organic vapour phase epitaxy using a two-temperature method has been investigated. The two-temperature growth method involves exposure of the uncapped InGaN quantum well to a temperature ramp in an ammonia atmosphere before growth of the GaN barrier at a higher temperature. The resulting quantum well, consists of interlinking InGaN strips containing gaps which may impede carrier diffusion to dislocations. By increasing the substrate misorientation from 0° to 0.5° we show that the density of InGaN strips increases while the strip width reduces. Our data show that the PL efficiency increases with miscut and that the peak efficiency occurs at a lower excitation power density.

Localization lengths of the electrons and holes in InGaN/GaN quantum wells have been calculated using numerical solutions of the effective mass Schr\"odinger equation. We have treated the distribution of indium atoms as random and found that the resultant fluctuations in alloy concentration can localize the carriers. By using a locally varying indium concentration function we have calculated the contribution to the potential energy of the carriers from band gap fluctuations, the deformation potential and the spontaneous and piezoelectric fields. We have considered the effect of well width fluctuations and found that these contribute to electron localization, but not to hole localization. We also simulate low temperature photoluminescence spectra and find good agreement with experiment., Comment: 7 pages, 7 figures

To enable the study of cavity quantum electro-dynamical effects in nitride systems, it is essential to be able to fabricate high quality cavity structures that exhibit large Q-values of the order of several thousands. A promising candidate for such a realisation is based around the micro-pillar distributed Bragg reflector (DBR) cavity. The growth of nitride stacks is problematic due to such material issues as lattice mismatch and dislocation propagation which seem to be more pronounced when compared to similar arsenide structures. In this paper we report on our efforts to characterize the homogeneity of our first generation planar DBR structures through both reflectivity measurements using the broadband output of a photonic crystal fiber (PCF) and cryogenic photoluminescence under ultraviolet (UV) excitation. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

III nitrides show interesting physical properties allowing many electronic and optoelectronic devices. Nitride growth is hampered by the lack of suitable substrates. Therefore nitride materials are grown on foreign substrates. Sapphire, SiC, and Si are most commonly used. These substrates have large lattice mismatches with respect to GaN of, respectively, +15%, +3.5%, and minus 17% [1]. SiC and Si do not allow direct growth of high quality GaN without Al(Ga)N interlayers whereas Sapphire is an insulator. A semiconductor substrate which allows high quality GaN growth without intermediate layers would allow the fabrication of heterostructure devices such as heterojunction bipolar transistors (HBTs). Recently we have found that direct growth of GaN on Ge(111) is relatively straightforward with Plasma Assisted Molecular Beam Epitaxy (PAMBE) [2]. A streaky reflection high energy electron diffraction (RHEED) pattern was observed immediately at the onset of growth and is maintained during growth. It was shown that aFWHM of the XRD rocking curve of only 371 arc seconds for a 38 nm GaN layer is possible. Fringes in the XRD omega/2theta scan indicated an abrupt interface between the GaN and Ge, see Figure 1. An advantage of GaN growth on Ge is the small thermal mismatch (minus 5.5%). The thermal mismatches between GaN and sapphire, SiC and Si are much larger: minus 34%, +25% and +54%, respectively [1]. Thermal mismatch leads to high thermally induced stress when cooling the sample down after growth and can lead to cracking. Structural investigations by TEM and XRD showed that it is energetically favorable to match the GaN and Ge crystals with a 4 ° twist with respect to each other. Two phases of GaN are created on a Ge(111) on axis substrate, each with a 4 ° twist. To obtain only one GaN phase, we investigated the use of off axis orientated Ge(111) substrates. From these investigations it is seen that off axis orientated Ge(111) substrates are succesful in obtaining only one GaN phase and reduce the number of defects inthe GaN layer. [1] L. Liu and J. H. Edgar, Mater. Sci. Eng., R. 37, 61 (2002). [2] R.R. Lieten, S. Degroote, K. Cheng, M. Leys, M. Kuijk and G. Borghs, Appl. Phys. Lett. 89, 2118 (2006)

Colin Humphreys and associates were instructed by Mr David Leeman of Higher Cowley Farm to undertake an archaeological assessment of the remains of a domestic building that now forms part of the complex of outbuildings to Higher Cowley Farm, Kentisbury. Higher Cowley farmhouse dates from the early 17th century, although the existing fabric may contain remnants of an earlier structure, and is grade II listed. The building in question has suffered severe storm damage (loss of roof etc.) late in 2001.

Etching, lithography, hole formation, surface restructuring and external machining can all be performed on a nanometre scale using an intense electron beam. Results are presented for a range of different materials which demonstrate the variety of mechanisms by which electron beam nano-etching can occur. For example, in crystalline 13-alumina hole formation occurs by surface indentations growing inwards to join up and form a nanometre diameter hole. In amorphous alumina, on the other hand, hole formation is from the inside-out: oxygen gas bubbles form under the electron beam, coalesce, and burst to leave a well defined nanometre diameter hole. In MgO and Si, holes develop from the electron exit surface: whereas in Al voids form along the irradiated volume, leading eventually to the development of a hole at the electron entrance surface. The potential of electron beam nano-etching to lithography and information storage is demonstrated by showing that the entire contents of the Encyclopaedia Britannica can be written on a pinhead.

This thesis describes results obtained using high resolution electron microscopy, acoustic microscopy and chemical analysis to study the structure and properties of the superionic β-aluminas.The acoustic microscopy and chemical analysis results relate solely to sodium β- and β" -alumina, which are used as the solid state electrolyte in the sodium/sulphur cell. The high resolution electron microscopy results cover sodium β- and β"-alumina as well as a number of ion-exchanged β"-aluminas.The β-alumina structure consists of spinel-like blocks separated by the so-called conduction planes. The conduction planes have a low density, and contain all the mobile cations. Lattice images of sodium β- and β"-alumina, silver β-alumina, ammonium/hydronium β"-alumina, gadolinium β" -alumina and divalent and trivalent europium β" -alumina are presented and discussed.A hitherto unreported long-period structure in sodium β-alumina is shown, as is superlattice ordering in the divalent and trivalent β"-aluminas.Defects in these materials are also discussed. The most common damage mode in the β" -aluminas, due to electron beam irradiation, is the loss of the mobile-ion containing planes, and the subsequent collapse and shear of the structure to form broad defect spinel blocks. It is shown that collapse vectors determined for sodium β"-alumina can also be applied to ammonium/hydronium β"-alumina. Two further damage modes observed in this β"-alumina are also discussed. A damage mode has been observed in sodium B-alumina and silver β-alumina which involves the extrusion of material to the crystal surface. Electron diffraction patterns from the extruded material have been indexed.The acoustic microscope has been used to examine bulk sodium β/β"-alumina electrolyte tube specimens. Images of rectangular features present in the tubes (approximately 40um in length) are presented and the possible nature of the features is discussed.

An 18-year-old patient of mine, currently under treatment for attention deficit hyperactivity disorder (ADHD) with methylphenidate, just found out that she is pregnant. What are the risks for the baby when the mother uses ADHD medications during pregnancy?Available evidence for amphetamines suggests no increased risk of malformations with use of therapeutic doses, and inadvertent exposure during pregnancy is unlikely to be harmful. Human data for methylphenidate and atomoxetine treatment in pregnancy are very limited. Documented cases do not suggest teratogenicity, but we cannot rule out this risk with the information available.

We present a comprehensive study of the emission spectra and electrical characteristics of InGaN/GaN multi-quantum well light-emitting diode (LED) structures under resonant optical pumping and varying electrical bias. A 5 quantum well LED with a thin well (1.5 nm) and a relatively thick barrier (6.6 nm) shows strong bias-dependent properties in the emission spectra, poor photovoltaic carrier escape under forward bias and an increase in effective resistance when compared with a 10 quantum well LED with a thin (4 nm) barrier. These properties are due to a strong piezoelectric field in the well and associated reduced field in the thicker barrier. We compare the voltage ideality factors for the LEDs under electrical injection, light emission with current, photovoltaic mode (PV) and photoluminescence (PL) emission. The PV and PL methods provide similar values for the ideality which are lower than for the resistance-limited electrical method. Under optical pumping the presence of an n-type InGaN underlayer in a commercial LED sample is shown to act as a second photovoltaic source reducing the photovoltage and the extracted ideality factor to less than 1. The use of photovoltaic measurements together with bias-dependent spectrally resolved luminescence is a powerful method to provide valuable insights into the dynamics of GaN LEDs.

This thesis describes the application of the well established technique of X-ray diffraction topography to a variety of problems, and includes considerations of the optimum conditions for taking rapid topographs. Chapter I contains a brief review of the subject together with an indication of the range of applicability. Several modifications of X-ray topography exist and several are briefly described to illustrate the principles and mechanisms of image formation. Contrast is formed in one or both of two ways. Regions of crystal may be so badly misoriented from the bulk, that no beams from the source can satisfy the reflection condition formulated by Bragg. This type of contrast is known as orientation contrast. The second type of contrast arises from the point to point lattice displacements giving a different reflecting power around the defect. This second type of contrast, termed extinction contrast, is dependent on the perfect crystal diffraction. A description of the different types of extinction contrast is given in terms of the dynamical theory of diffraction in a perfect crystal and the significance of the direct, intermediate, and dynamical images stressed. The chapter concludes by sketching some of the important fields of application. The second chapter is concerned with the relative merits of scanning and wide beam X-ray topography. A description of the technique of wide beam topography using the Kandbeta; line is given and it is demonstrated that the resolution is as good as that using Lang's scanning technique. A new wide beam method using the tungsten Landalpha;1 line is proposed and demonstrated. From expressions derived for the exposure times, it is seen that the important parameter to maximise is the power per unit horizontal length of the X-ray source. The speeds of the two techniques are compared for a variety of generators and the advantage of using an Elliott GX6 is made clear. A direct imaging system is clearly preferable in principle to film recording and Chapter III is devoted to a discussion of such systems. Following a review of previously developed imaging systems, a new method of directly displaying X-ray images using a channel plate is demonstrated. The remainder of the chapter gives detailed calculations of the efficiency of a channel plate to X-rays in the wavelength region 0.5andndash;2andnbsp;andAring;. Using published data, the efficiency is calculated for several cases and compared with previous experimental work. To better than an order of magnitude, these efficiencies may be used to predict the intensity of the image produced on the image converter screen. Chapter IV falls into two sections. The first describes an experiment to determine the minimum thickness at which dislocations are visible in crystals using normal topographic techniques. It was found that the value was dependent on the fraction of the material thickness taken up by misoriented material. This explanation was found to be in qualitative agreement with experiment, the minimum thickness fell from O.4 of an extinction distance for the low order reflections to 0.2 of an extinction distance for high order reflections. The second part consists of a comparison between experimental image profiles and those simulated on a computer. Quite reasonable agreement was found and the sources of error in the method of computing and ways to avoid them are discussed in terms of practical and basic limitations. The remainder of this thesis describes application of X-ray topography to four different types of material. Chapter V is devoted to a study of defects in a silicon slice following device fabrication. Interest in the effect of crystallographic defects on the performance of integrated circuit devices has led to a large number of investigations over the last decade and these are reviewed and their conclusions summarised. An attempt is made to measure the stress at the junction edge, produced by the mismatch in the ionic radii between dopant and matrix. As a result of approximations in the theory and measurements, the force per unit length of junction, measured to be 2 andtimes; 104 dynes/cm, must be taken as order of magnitude only. Similarly, only an order of magnitude estimate of the stress is permissible. There follows a description of a combined Scanning Electron Microscope and X-ray topographic experiment to determine the cause of breakdown fingers, sometimes seen at the junction edges in the beam induced conductivity mode in the S.E.M. It is concluded that they are due to scratches in the oxide mask prior to diffusion. The rest of the chapter is given to a detailed description of dislocations and their contrast observed in a silicon slice heavily doped with boron. The slip behaviour is not analysed in detail, but seems to support the conclusion that this deformation, due to thermal shock, is independent of the doping. Interactions between 'emitter edge' dislocations are described and the anomalously narrow image widths of such dislocations explained by considering the effects of overlapping strain fields. Burgers vectors of dislocations inside the diffused regions are determined, and the contrast of these dislocations at high density is interpreted as an effect due to overlapping images. Interactions between the 'inside' and 'emitter edge' dislocations are described. In regions where the dislocation density was low, the dislocations exhibited a reversal of contrast on reversal of the diffraction vector. With the diffraction vector parallel to the dislocation line, the contrast was black-white, reversing with the diffraction vector. With the diffraction vector at 60° to the line, the contrast was either black or white, reversing with the diffraction vector. This effect is interpreted in terms of surface relaxation and computations performed using the Penning-Polder theory are in qualitative agreement with the experimental results. Chapter VI describes the application of X-ray topography to the study of defects in natural fluorite. Dislocations are identified with Burgers vectors parallel to andlang;101andrang; directions. These are nearly pure edge in character and the Burgers vector is presumed to be 1andfrasl;2 andlang;101andrang;. A direct correspondence is observed between bundles of dislocations and regions of birefringence contrast. A uniform birefringence contrast in the matrix, which can not be explained in terms of dislocation stress, is also observed. This is explained in terms of impurity atoms, sited between {111} planes during growth, distorting the crystal normal to the {111} faces. The boundaries between regions of birefringence lie along inclined andlang;110andrang; directions and on this model, no strain is associated with these boundaries, in agreement with the X-ray topographic evidence. Extensive planar faults, lying on {111} planes and with fault vector a non integral value of the lattice spacing, are postulated to be thin lamellae of material containing markedly different impurity concentration. In Chapter VII, some vapour grown layer compounds are studied. Individual dislocations are resolved in SnSe2, TiSe2, SnS2, TiS2, ZrS2 and HfS2. The Burgers vectors of the dislocations in SnS2 were determined and their origins discussed. Large area stacking faults bounded by 1andfrasl;3 andlang;1100andrang; partial dislocations are also observed in these specimens. Dislocation and defect configurations in the other compounds are described and a modified divergent beam method for taking topographs of bent crystals is demonstrated. Some preliminary experiments on pure iron are described in Chapter VIII. Contrast is observed suggestive of dislocation helices and rows of loops in these strain-anneal grown crystals. Arrays of dislocations of pure edge type and Burgers vector parallel to [100] are interpreted as being contained in a low angle boundary wall, following Futagami. The tilt angle across such boundaries is measured to be a few seconds of arc. Finally, Chapter IX suggests a few directions for further investigation.

Zinc oxide (ZnO) has long been advanced as a low cost, earth-abundant transparent conducting oxide (TCO) with potential as a replacement for high-performance, but costly, indium oxide (In2O3) based materials in a wide range of technological applications. However, despite decades of research and development efforts, ZnO-based materials have still failed to displace the incumbents in any large-scale applications. Given the compelling materials cost advantages of ZnO, it is almost certain that its poor adoption is due to deficits in its technical performance. This thesis aims to fulfill the need for systematic, fundamental work to identify and examine the factors that limit TCO performance, and in particular, those that limit ZnO relative to In2O3. Using spray pyrolysis as the primary deposition method, many different series of ZnO and In2O3 films have been prepared and examined using a range of chemical, structural, and optoelectronic characterization techniques. After essential background information on the basic physics and chemistry of TCOs, as well as a detailed discussion of the chosen deposition and characterization methods, three main classes of performance limitations will be covered: 1) those related to the intrinsic properties of electronic transport in crystalline TCO domains, 2) those arising in the course of impurity doping, and 3) those occurring due to grain boundary effects and the polycrystalline nature of thin film TCO samples. Taken together, these results will show that preparing ZnO-based TCOs with performance approaching that of the best In2O3-based materials, while very likely to be technically possible, will almost certainly involve overcoming significant engineering and process development challenges that, importantly, are not required to make high quality In2O3. Ultimately, whether ZnO will ever find significant, real-world use as a TCO will depend on whether the deep differences between ZnO and In2O3 performance limits that will be highlighted and examined in this thesis can be bridged in a practical and cost-effective manner.

The judicial primers project is a unique collaboration between members of the judiciary, the Royal Society and the Royal Society of Edinburgh. The primers have been created under the direction of a Steering Group initially chaired by Lord Hughes of Ombersley who was succeeded by Dame Anne Rafferty DBE, and are designed to assist the judiciary when handling scientific evidence in the courtroom. They have been written by leading scientists and members of the judiciary, peer reviewed by practitioners and approved by the Councils of the Royal Society and the Royal Society of Edinburgh.\ud Each primer presents an easily understood, accurate position on the scientific topic in question, and considers the limitations of the science and the challenges associated with its application. The way scientific evidence is used can vary between jurisdictions, but the underpinning science and methodologies remain consistent. For this reason we trust these primers will prove helpful in many jurisdictions throughout the world and assist the judiciary in their understanding of scientific topics. The primers are not intended to replace expert scientific evidence; they are intended to help understand it and assess it, by providing a basic, and so far as possible uncontroversial, statement of the underlying science.