Nickel Silicide as a Contact and Diffusion Barrier for Copper Metallization in Silicon Photovoltaics

In this study, NiSi has been formed as the contact for copper front metallization on laboratory silicon solar cells. Transfer length method (TLM) measurements were used to examine the resistive nature of the contact. The scalability of the measurement itself was also examined. Characterization of the NiSi films for thickness, resistivity and composition were performed. Single crystal silicon solar cells were fabricated and used in temperature stress tests of the degradation of the pseudo-fill factor (pFF) and quantum efficiency (QE) to assess the capabilities of the NiSi diffusion barrier. Best contact resistivities of 7.3e-6 Ohm-cm2 with NiSi only and 4.0e-5 Ohm-cm2 with NiSi/Cu/TiN were measured. Even following a week of temperature stress, NiSi maintained solar cell performance parameters such as pseudo fill factor (pFF) and quantum efficiency (QE) better than Cu/TiN contacts without NiSi and at least as good as Ti/Pd/Ag contacts on average. These methods and materials were applied to high efficiency, textured, solar cells with passivated tunneling contacts. The viability of NiSi in this regime was evaluated by photoluminescence (PL), optical, and TLM measurements. Although the NiSi contact was shown to damage the passivation quality of the contact, a cell capable of an open circuit voltage near 700 mV could be produced using such a contact scheme. Contact resistances as low as 1.8 mOhm-cm2 were formed, as compared with industry standard screen printed Ag contacts which form best contact resistivities in the range of 1.5 mOhm-cm2

The metaverse—Not a new frontier for crime.

Law enforcement co-ordination agencies have recently issued position/guidance documents relating to the potential for VR environments (the “Metaverse”) to become new environment for criminal activity, and calling for additional work to enhance investigative capability. By reviewing the historic development of VR and comparing it with the appearance of the WWW, the authors propose that the situation is not as dire as the issued documents may suggest, but represents an evolutionary rather than revolutionary step in online experiences. They conclude, therefore, that while ability to examine VR presentation/interaction devices may be useful, continued development of ability to examine online systems remains essential

Digital Evidence Regulation - an assessment of underlying issues in England and Wales

In the field of Digital Forensics, in England and Wales, the author has published a study of technical requirements found in Standard Operating Procedures and validation methods, evaluated potential mechanisms for producing evidence of verification as a means of reducing the validation and re-validation effort required, and examined the use of language in various documents produced, and referenced, by the Forensic Science Regulator. From this work, he argues that the current situation re validation may be giving a false sense of assurance that technical requirements are being satisfied, that it should be possible for evidence of verification to be made available to solve this problem, without requiring full disclosure of commercially sensitive or secret methods, and that the situation may have arisen through poor use of language in the Regulator’s guides. He also suggests that the FSR’s guides may have allowed, or caused, Digital Forensic Laboratories to ignore or misunderstand the importance of technical requirements in Standard Operating Procedure design and validation. Finally, having observed the lack of interest in the FSR’s work and in method validation in court proceedings, he considers, from a lay perspective, the legal position relating to admissibility of computer-derived and computer-generated evidence. From this, he argues that the legal precedents are not entirely valid in the context of modern systems, and proposes a new classification of digital forensic systems which takes account of the increasingly automated analysis present in these tools

Really proper dangerous one: Aboriginal responses to the first wave of COVID-19 in the Kimberley

https://researchonline.nd.edu.au/nulungu_reports/1002/thumbnail.jp

Requirements in digital forensics method definition : Observations from a UK study

During a project to examine the potential usefulness of evidence of tool verification as part of method validation for ISO 17025 accreditation, the authors have examined requirements statements in several digital forensic method descriptions and tools. They have identified that there is an absence of clear requirements statements in the methods and a reluctance or inability to disclose requirements on the part of tool producers. This leads to a break in evidence of correctness for both tools and methods, resulting in incomplete validation. They compare the digital forensics situation with other ISO 17025 accredited organisations, both forensic and non-forensic, and propose a means to close the gap and improve validation. They also review existing projects which may assist with their proposed solution

Strengthening impact assessment: a call for integration and focus

We suggest that the impact assessment community has lost its way based on our observation that impact assessment is under attack because of a perceived lack of efficiency. Specifically, we contend that the proliferation of different impact assessment types creates separate silos of expertise and feeds arguments for not only a lack of efficiency but also a lack of effectiveness of the process through excessive specialisation and a lack of interdisciplinary practice. We propose that the solution is a return to the basics of impact assessment with a call for increased integration around the goal of sustainable development and focus through better scoping. We rehearse and rebut counter arguments covering silo-based expertise, advocacy, democracy, sustainability understanding and communication. We call on the impact assessment community to rise to the challenge of increasing integration and focus, and to engage in the debate about the means of strengthening impact assessment

Impaired value-based decision-making in Parkinson’s Disease Apathy

Apathy is a common and disabling complication of Parkinson’s disease characterized by reduced goal-directed behaviour. Several studies have reported dysfunction within prefrontal cortical regions and projections from brainstem nuclei whose neuromodulators include dopamine, serotonin and noradrenaline. Work in animal and human neuroscience have confirmed contributions of these neuromodulators on aspects of motivated decision-making. Specifically, these neuromodulators have overlapping contributions to encoding the value of decisions, and influence whether to explore alternative courses of action or persist in an existing strategy to achieve a rewarding goal. Building upon this work, we hypothesized that apathy in Parkinson’s disease should be associated with an impairment in value-based learning. Using a four-armed restless bandit reinforcement learning task, we studied decision-making in 75 volunteers; 53 patients with Parkinson’s disease, with and without clinical apathy, and 22 age-matched healthy control subjects. Patients with apathy exhibited impaired ability to choose the highest value bandit. Task performance predicted an individual patient’s apathy severity measured using the Lille Apathy Rating Scale (R = −0.46, P &lt; 0.001). Computational modelling of the patient’s choices confirmed the apathy group made decisions that were indifferent to the learnt value of the options, consistent with previous reports of reward insensitivity. Further analysis demonstrated a shift away from exploiting the highest value option and a reduction in perseveration, which also correlated with apathy scores (R = −0.5, P &lt; 0.001). We went on to acquire functional MRI in 59 volunteers; a group of 19 patients with and 20 without apathy and 20 age-matched controls performing the Restless Bandit Task. Analysis of the functional MRI signal at the point of reward feedback confirmed diminished signal within ventromedial prefrontal cortex in Parkinson’s disease, which was more marked in apathy, but not predictive of their individual apathy severity. Using a model-based categorization of choice type, decisions to explore lower value bandits in the apathy group activated prefrontal cortex to a similar degree to the age-matched controls. In contrast, Parkinson’s patients without apathy demonstrated significantly increased activation across a distributed thalamo-cortical network. Enhanced activity in the thalamus predicted individual apathy severity across both patient groups and exhibited functional connectivity with dorsal anterior cingulate cortex and anterior insula. Given that task performance in patients without apathy was no different to the age-matched control subjects, we interpret the recruitment of this network as a possible compensatory mechanism, which compensates against symptomatic manifestation of apathy in Parkinson’s disease.</p