New insights into perovskite semiconductors for electronic applications

• Autor(a) principal: Marques, Miguel João Bolacha
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/94397
• topic: Transparent semiconductors; Organolead mixed-halide perovskites; Highmobility ambipolar thin-films; P-type charge concentration; Polycrystalline ion migration; Negative capacitance; Domínio/Área Científica::Engenharia e Tecnologia::Nanotecnologia

Transparent semiconductors are a type of materials distinguished by high transmission of light in visible region and relatively high electrical conductivity. These materials show diverse applications in the fields of solar energy and optoelectronics, being considered one of the most successful everyday products as they’re installed everywhere, like window electrodes in smartphones and solar panels. For n-type semiconductors is easy to obtain high carrier mobility, which is not the case for p-types. Developing p-type high mobility devices proves to be difficult given the nature of valence bands in most oxides, generally leading to large hole effective mass and poor charge conductivity. This current situation limits advances on thin-films technology, restraining materials band matching possibilities and unfulfilling goal creation of devices with both p- and n-type materials, hence denying improvements in transparent electronics. However, in recent studies, p-type perovskite-structured semiconductors with low fabrication cost and several applications have shown to possess excellent transparent semiconductor qualities, thus being a potential for the future of electronics and photovoltaics. In this work, mixed halide – iodine and bromine – organolead-based perovskite semiconductor thin-films (3−) were subjected to absorbance, thickness and structural characterizations, and then, dielectric and conductive layers were added to analyze semiconductor carrier properties, metal-oxide-semiconductor (MOS) capacitance and thin-film transistor (TFT) output. As a result, p-type and n-type hall mobilities of 20.22/ and 38.12/, respectively, were achieved by 3− polycrystalline thin-films, negative capacitance and ion migration were identified in MOS capacitors, and relatively high field-effect mobility was estimated for the fabricated TFTs. These analyses show one thing in common, more ambipolar characteristics confirmed by increasing bromine contents.