<p>This paper presents reliable synthesis of germanium nanowires by the vapor-liquid-solid method using copper as an alternative catalyst to gold, the most commonly used metal. The morphological study showed long range single-crystalline germanium nanowires with diamond structure and diameters ranging from 20 nm to 80 nm and lengths in tenths of a micrometer, which was much larger than the cross-section. In an investigation of electronic properties, devices built from a thin film of nanowires were studied and the semiconductor behavior of the samples confirmed, with variable range hopping identified as the main transport mechanism. Additionally, metal-nanowire contact behavior - ohmic or with Schottky barrier - was found to depend on the metal used in the device. Therefore, the possibility of controlling current-voltage behavior combined with the good crystalline quality of the nanowires renders these nanostructures an attractive option for future electronic and optoelectronic applications.</p>

O estudante que se dispõe a analisar propriedades de materiais, através da utilização das técnicas espectroscópicas baseadas nos princípios de absorção no infravermelho, na luminescência e no espalhamento Raman, costuma encontrar dificuldades quanto às informações que podem ser acessadas em cada caso, sobre a escolha da técnica mais conveniente para estudar determinado fenômeno e, principalmente, sobre o cruzamento das informações obtidas com cada uma das três técnicas. Neste artigo, visando facilitar o aprendizado do uso mais racional dessas técnicas, procuramos então sintetizar como os princípios físicos fundamentais de cada técnica determinam seu uso - individual ou de forma complementar - para explorar suas potencialidades na expectativa de melhor caracterizar as propriedades dos materiais analisados.

It is quite common that the student engaged in the analysis of properties of materials using spectroscopic techniques based on the effects of infrared absorption, luminescence and Raman scattering, faces difficulties such as the interpretation of the information that can be accessed in each case, the choice of the best technique in order to study a specific phenomenon and, especially, the cross-checking of the information obtained in each one of the three techniques. Trying to make easier the apprenticeship of the rational use of these techniques, we summarize in this paper the fundamental physical principles related to each one of them, and how these principles determine their employment - individually or in a complementary way - to explore their potentiality towards better characterizing the desired properties.