Role of Contacts in Capacitance Measurements of Solar Cells

The electronic properties of low cost, thin-film solar cells are complicated by the non-ideal nature of the semiconductor layers. Typically, the fundamental electronic properties of such materials are evaluated using current-voltage and capacitance-voltage measurements. However, in these devices, it is common for the back contact to be non-ohmic. We are exploring the impact of such a back contact on the outcome of standard capacitance-based characterization techniques. We compare computer models of capacitance response with measurements of simple model electronic circuits and of solar cell devices

Self-Regulation in a Kindergarten Classroom

Self-regulation in a kindergarten classroom is something that every student has to learn when entering school. With the help and support of the teacher, it is beneficial to students and their classmates if they can have body regulation during learning time. What are ways that kindergarten students can effectively self-regulate and what are the positive effects in the classroom? How can teachers support the student’s self-regulation in the classroom setting? As a response, a self-regulation station was set up from the beginning of the school year gathering data for 4 months. Large group instruction, modeling and using specific terms of monitoring self-regulation were used. In the station students chose to use belly-breathing or the breathing ball to focus on themselves and their deep breathing. Kindergarten students enter their schooling at different levels of self-regulation and various backgrounds. Each child also has different life experiences that effect their behavior in the classroom setting for the first time. In conclusion to this study, most kindergartners could self-regulate with the help of the teacher and the consistency of the self-regulation station. The classroom environment showed an increase in uninterrupted learning following after providing the positive outcomes of the self-regulation station. The independent levels in the students were also evident. In contrast, the time of the year and days of the week play a role in how well a kindergartner can self-regulate

SupportingChildrenWithBurns.co.uk: Reporting on 3 years of use of a website developed for the psychosocial support of parents of burn-injured children

© 2022 The British Psychological Society. This is the accepted manuscript version of an article which has been published in final form at https://www.bps.org.uk/publications/clinical-psychology-forumSupportingChildrenWithBurns.co.uk was developed and tested with UK-based parents, burn-care professionals, and members of support organisations. The aim being to create an innovative patient-centred resource, tailored to meet the specific needs of parents/carers of children with burn-injuries, that would be a valuable addition to paediatric burn-care (Heath, 2020). Whilst websites can never replace the services offered by the NHS, or address the challenges they face, it was hoped that the resource could support services and charities in providing the best care to patients/families in line with models of stepped-care. Having a trusted resource that parents can access any time/place, providing advice for self-care, whilst also normalising access to support, and directing parents to different forms of formal/informal support, may mean that more parents find their needs are, or can be, met. Evaluation of the website is important to ensure that it is being accessed and to drive future development. Data regarding public access to, and use of, the website over three years (17.10.2018 to 13.10.2021) has been collated using Google Analytics and analysed using descriptive statistics. Data demonstrates that the website is currently visited an average of 192-times-per-month from users around the world. Information regarding which pages are visited, most often and for longest, suggests that parents’ primary focus is their injured child, not their own psychosocial needs; however, accessing information/advice, and seeking shared experiences from peers, is also sought and valued. Further evaluation of the website’s impact on the emotional wellbeing of parents/carers following a child’s burn-injury would be welcomed.Peer reviewe

Depression: An antecedent and consequence of burn-injuries to children

Accidents are inevitable but burn injuries can be traumatic and distressing for the affected individual and their family, with a prolonged period of recovery. In this short review, emotional difficulties in parents (particularly depression) as both an antecedent and a consequence of burn injuries to children will be discussed, as well as intervention considerations to help families to cope with such distress

New technologies in burn care: A clinical psychologist’s perspective of opportunities for advancing psychosocial care

British Burn Association 2017 Laing Essay Prize Winne

Frequency and Voltage Dependence of Series Resistance in a Solar Cell

While admittance measurements of solar cells are typically conducted in reverse or at zero bias, and analyzed using the depletion approximation, the operating point of the solar cell is in forward bias, and the series resistance is often estimated using IV curves with a high forward current. In this mode, the device is no longer in the depletion regime, and the large number of injected minority carriers alters the transport properties significantly. In our Cu(In,Ga)Se2 devices, we measure negative values of capacitance at high forward bias, which may be linked to injected minority carriers and carrier transport limitations, although our calculations of capacitance may also be influenced by series resistance. In this study, we compare AC and DC measurements of voltage dependent series resistance to try to better understand the negative capacitance signal

Peer-informed support for parents of burn-injured children

Burns are the fifth most common cause of non-fatal childhood injuries. In addition to the trauma of suffering a burn, the painful and intrusive medical procedures required to treat them can impact on the developing child cognitively, emotionally, psychologically, and socially. A child’s burn injuries and their treatment can also have a significant psychosocial impact on parents, affecting their health and mental well-being. Parents can experience a reactive distress including elevated stress, anger, anxiety, depression, post-traumatic stress, guilt, marital and financial problems, and increased responsibility and load, during the acute phase of treatment. Many must also divide their time to meet the needs of any uninjured siblings, and between work, the hospital ,and home. This PhD used mixed methods to explore the experiences, access to support, opinions of peer support, and support needs amongst parents and carers of burn-injured children. Thirteen interviews were conducted with parents, followed by a survey of a further 57 parents. The majority of parents reported that they were offered support, particularly during the acute phase of treatment. Most often, this was from nursing staff. Despite this, many parents also reported to feel isolated. Access to peer support has been recommended in the British Burn Care Standards (2013, 2018), and parents recognised the potential value of this. However, factors such as guilt, the pain of recollection, perceived stigma, time pressures, and distance to the hospital can make accessing such support difficult. The results of this research suggested that online delivery of supportive peer-informed information could be particularly appealing to parents, particularly that which retained the peer voice. With widespread access to the internet and growing dependence on computers and mobile devices, it is common for adults in the UK to seek health-related support and information on the Internet. Many parents involved in this research had searched online for burn-related information following their child’s injury but found this to be lacking. Therefore, using a partnership-based method of website development, www.SupportingChildrenWithBurns.co.uk was developed and tested with nine parents and 22 professionals before being publicly released and accessed worldwide. An initial evaluation of the performance of this new resource over the first 6 months is provided

Exploring the Electrical Properties of Twisted Bilayer Graphene

Two-dimensional materials exhibit properties unlike anything else seen in conventional substances. Electrons in these materials are confined to move only in the plane. In order to explore the effects of these materials, we have built apparatus and refined procedures with which to create two-dimensional structures. Two-dimensional devices have been made using exfoliated graphene and placed on gold contacts. Their topography has been observed using Atomic Force Microscopy (AFM) confirming samples with monolayer, bilayer, and twisted bilayer structure. Relative work functions of each have been measured using Kelvin Probe Force Microscopy (KPFM) showing that twisted bilayer graphene has a surface potential 20mV higher than that of monolayer graphene and 35 mV below bilayer graphene

Scanning Capacitance Spectroscopy on n\u3csup\u3e+\u3c/sup\u3e-p Asymmetrical Junctions in Multicrystalline Si Solar Cells

We report on a scanning capacitance spectroscopy (SCS) study on the n+-p junction of multicrystalline silicon solar cells. We found that the spectra taken at space intervals of ∼10 nm exhibit characteristic features that depend strongly on the location relative to the junction. The capacitance-voltage spectra exhibit a local minimum capacitance value at the electrical junction, which allows the junction to be identified with ∼10-nm resolution. The spectra also show complicated transitions from the junction to the n-region with two local capacitance minima on the capacitance-voltage curves; similar spectra to that have not been previously reported in the literature. These distinctive spectra are due to uneven carrier-flow from both the n- and p-sides. Our results contribute significantly to the SCS study on asymmetrical junctions

Effect of Ga Content on Defect States in CuIn\u3csub\u3e1-x\u3c/sub\u3eGa\u3csub\u3ex\u3c/sub\u3eSe\u3csub\u3e2\u3c/sub\u3e Photovoltaic Devices

Defects in the band gap of CuIn1-xGaxSe2 have been characterized using transient photocapacitance spectroscopy. The measured spectra clearly show response from a band of defects centered around 0.8 eV from the valence band edge as well as an exponential distribution of band tail states. Despite Ga contents ranging from Ga/(In+Ga)=0.0 to 0.8, the defect bandwidth and its position relative to the valence band remain constant. This defect band may act as an important recombination center, contributing to the decrease in device efficiency with increasing Ga content