Silke Rönnebeck

Crystal Orientation Dependence and Anisotropic Properties of Macropore Formation of p- and n-Type Silicon

The dependence of macropore morphology on the orientation of p- and n-type silicon samples was studied for various organic and aqueous electrolytes containing hydrofluoric acid. Scanning electron microscopy was used studying the morphology of the maeropores. The results show that the macropore formation in p- and n-type silicon is a strongly anisotropic process. Depending maeropores. The results show that the macropore formation in p- and n-type silicon is a strongly anisotropic process. Depending on the substrate orientation and preferred growth directions could be observed. The mierostructure of macropores was studied by analytical and high-resolution transmission electron microscopy. The surface of macropores in n- and p-type Si(001) shows {111} facets indicating that {111} planes are stabilized against further dissolution. Breakthrough pores show very specific anisotropic properties independent of the electrolyte. These pores consist of periodic arrangements of truncated octahedral voids with {111} walls strung up in directions. The erystal orientation dependence of pore formation reflects specific properties of the pore formation mechanism and one of the important electrolyte parameters is the ability to form an anodic oxide. Macropores formed in more strongly oxidizing electrolytes tend to have smoother macropore walls.

Searching for a common ground – A literature review of empirical research on scientific inquiry activities

Abstract Despite the importance of scientific inquiry in science education, researchers and educators disagree considerably regarding what features define this instructional approach. While a large body of literature addresses theoretical considerations, numerous empirical studies investigate scientific inquiry on quite different levels of detail and also on different theoretical grounds. Here, only little systematic research has analysed the different conceptualisations and usages of the overarching construct of scientific inquiry in detail. To close this gap, a review of the research literature on scientific inquiry was conducted based on a widespread approach to defining scientific inquiry as activities that students engage in. The main goal is to provide a systematic overview about the range and spectrum of definitions and operationalisations used with regard to single activities of the inquiry process in empirical studies. The findings from the review first and foremost illustrate the variability in the ways these activities have been operationalised and implemented. For each activity, studies differ significantly not only with respect to the focus, explicitness and comprehensiveness of their operationalisations but also with regard to the consistency of their implementation in the form of instructional or interventional components in the study and/or in the focus of the assessment of student performance. This has significant implications regarding the validity and comparability of results obtained in different studies, e.g. in the context of discussions concerning the effectiveness of inquiry-based instruction. In addition, the interrelation between scientific inquiry, scientific knowledge and the nature of science seems to be underexplored. The conclusions make the case for further theoretical work as well as empirical research.

Crystal Orientation Dependence of Macropore Formation in n-Si With Backside-Illumination in HF-Electrolyte

The formation of macropores on anodically biased n-type silicon with backside-illumination was investigated as a function of crystal orientation and bias voltage. Specimens were cut from bulk crystals with various orientations from {100} to {111}, polished and subjected to anodic etching in HF. The resulting pores were investigated on cleaved samples by SEM. All pores were found to grow in either a 〈100〉 direction or a 〈113〉 direction, depending on the misorientation angle. This finding applies also to the branching of a single pore. The results can be understood if the valence for the dissolution reaction is approximately 2.6 in 〈100〉 and approximately 4 in the 〈113〉 direction, and if all other directions are not allowed for the growth of pores in Si.

Written Teacher Feedback: Aspects of Quality, Benefits and Challenges

Written feedback provided by the teacher to his or her students is an important aspect of formative assessment. After a theoretical introduction to teacher prerequisites for giving feedback and to the quality of written feedback in general, results from an implementation of feedback methods in classrooms will be described for the cases of Germany, Switzerland and Denmark. The focus will be on the inquiry method ‘investigation in science’ that requires from students such competences as planning and/or conducting experiments. This study examines the quality of written teacher feedback which was provided based on rubrics and templates for open comments. For this purpose, written teacher feedback itself, student artefacts and data from questionnaires were analysed. Furthermore, the benefits and challenges that teachers noticed in using written feedback will be examined. Finally, it will be discussed which means of support for teachers seem necessary in order to foster the implementation of written teacher feedback as part of formative assessment in inquiry-based science education.

European Educational Systems and Assessment Practice

This chapter surveys the status of educational systems and assessment practices across eight European countries that are part of the ASSIST-ME project. First, variations in the country’s educational systems are examined to identify possible connections between systems and educational practices. Such associations are useful both for understanding different existing assessment conditions as well as for providing possible pathways for change. Next, the chapter takes a closer look at teacher practices in these educational systems in order to identify the actual assessment practices of teachers in each country. With these understandings of the systems and current uses of assessment, it is possible to identify affordances and challenges for improving assessment practices.

The Concept of Competence and Its Relevance for Science, Technology and Mathematics Education

Since the beginning of the twenty-first century, the concept of competence has been introduced as a new paradigm in several educational systems. It reflects the need of educational systems to respond to societal and economic changes, i.e. the transition from industrial- to information-based societies. In contrast to earlier educational goals that focused more on basic skills and knowledge expectations, competences are more functionally oriented. They involve the ability to solve complex problems in a particular context, e.g. in vocational or everyday situations. In science, technology and mathematics education, the concept of competence is closely linked to the concept of literacy. Apart from these rather cognitive and affective perspectives influenced by the need to assess students’ achievement of desired learning goals in relation to their interest and motivation, the perspectives of the concept of Bildung as well as of the labour market influence today’s definition of educational goals. In order to address these perspectives, twenty-first-century skills were defined that encompass skills believed to be critically important to success in today’s world like, e.g. innovation and communication. This chapter addresses these developments by describing the concept of competence, by explaining its relevance for science, technology and mathematics education and by examining future directions. The chapter concludes with some remarks regarding commonalities and differences between the three domains: science, technology and mathematics.

The Teaching and Assessment of Inquiry Competences

New competence-oriented learning goals can only be sustainably implemented if they are aligned with teaching and assessment goals. Within the fields of science, technology and mathematics education, one approach of competence-oriented teaching is based on the concept of inquiry-based education. Scientific inquiry in science, problem solving in mathematics, design processes in technology and innovation as a cross-curricular approach to teaching and learning that is emphasised as a key element of twenty-first-century skills allow students to engage in the thinking and working processes of scientists. By applying these approaches, teachers can address subject-specific as well as generic competences (e.g. investigation in science as a subject-specific competence vs. argumentation or communication as more generic competences). Since what is assessed strongly influences what is taught, changes in teaching need to be accompanied by changes in assessment in order to be sustainable. Teaching and learning goals need to be aligned, and assessment methods developed that allow for the assessment of competences related to scientific inquiry, mathematical problem solving or design and innovation processes. This chapter aims to provide a short overview about these inquiry-based approaches in the teaching and learning of science, technology, mathematics and innovation. Following a short introduction, the chapter consists of four subsections devoted to scientific inquiry, mathematical problem solving, design processes and innovation. Each subsection addresses three basic questions: (1) How is the construct defined and conceptualised? (2) How does teaching for inquiry change teaching? (3) What changes in assessment are necessary to assess inquiry competences?