Pulsed laser ablation of silicon: the influence of beam parameters on ablated crater morphology

Laser micromachining is one of the principal fields where the laser capability to change the material morphology is frequently applied and silicon is still the element most used in the semiconductor and photovoltaic industries despite the recent studies on new materials. Although various models reported in the literature describe the laser material interaction, the relation between the ablated crater morphology and the laser beam parameters remains unclear or does not give methods and equations that can be applied on the engineering environment. The aim of this thesis is to reduce the knowledge gap of the understanding of three laser parameters (pulse duration, energy beam shape, and polarisation) influence on the ablated crater morphology by providing functions and relations that can be applied in the engineering environment. First, a systematic study on laser pulse duration based on two different functions (i.e. thermal-based and non-thermal based) is carried out, then the impact of the thermal effect on crater morphology of two non-standard energy beam distributions (i.e. round flat-top and square-top) is evaluated, and finally the laser polarisation effects in the non-linear laser ablation regime are explored, providing the engineering environment of new functions and relations between laser beam parameters and crater morphology

Body Representations in Children with Cerebral Palsy

We constantly process top-down and bottom-up inputs concerning our own body that interact to form body representations (BR). Even if some evidence showed BR deficits in children with cerebral palsy, a systematic study that evaluates different kinds of BR in these children, taking into account the possible presence of a general deficit affecting non-body mental representations, is currently lacking. Here we aimed at investigating BR (i.e., Body Semantics, Body Structural Representation and Body Schema) in children with cerebral palsy (CP) taking into account performance in tasks involving body stimuli and performance in tasks involving non-body stimuli. Thirty-three CP (age range: 5–12 years) were compared with a group of 103 typically-developing children (TDC), matched for age and sex. 63.64% of children with CP showed a very poor performance in body representation processing. Present data also show alterations in different body representations in CP in specific developmental stages. In particular, CP and TDC performances did not differ between 5 to 7 years old, whereas CP between 8 and 12 years old showed deficits in the Body Structural Representation and Body Schema but not in Body Semantics. These findings revealed the importance of taking into account the overall development of cognitive domains when investigating specific stimuli processing in children who do not present a typical development and were discussed in terms of their clinical implications

Layer separation driven by laser-induced strain in semiconductor thin film

The scribing of the semiconductor layer in thin-film solar cells is here achieved by means of laser induced thermal gradient and mechanical strain. We experimentally demonstrate the scribing by separating one layer from a underlying layer without a substantial melting phase. The modeling of the process was used to predict the spatio-temporal distribution of the induced effects, the resulting scribed channel is confined and the process has a good repeatability. We envisage a parallelization of the process for simultaneous cell formation on the panel