A5061891178- Advanced Thermoelectric Materials and Devices
- Advanced Semiconductor Detectors and Materials
- Chalcogenide Semiconductor Thin Films
- Wood Treatment and Properties
- Topological Materials and Phenomena
- Tree Root and Stability Studies
- Forest ecology and management
- 2D Materials and Applications
- Semiconductor Quantum Structures and Devices
- Lignin and Wood Chemistry
- Quantum and electron transport phenomena
- Electronic and Structural Properties of Oxides
- Surface and Thin Film Phenomena
Universidade Federal de Itajubá
2017-2019
University of Lisbon
2014
In this work, bismuth telluride films are grown by molecular beam epitaxy (MBE) on (111) BaF2 substrates, using stoichiometric Bi2Te3 and additional Te solid sources. The growth dynamics structural defects investigated in detail as function of substrate temperature, flux extra supply, means atomic force microscopy, Raman spectroscopy reciprocal space mapping. rate increases linearly with the most appropriate conditions to grow high-quality single layers is found be a narrow window MBE...
We investigated the photoconductivity effect in $p$-type $\mathrm{P}{\mathrm{b}}_{1\ensuremath{-}x}\mathrm{E}{\mathrm{u}}_{x}\mathrm{Te}$ films for $x=0.01$, 0.02, 0.03, 0.05, and 0.06 at $T=300\phantom{\rule{0.16em}{0ex}}\mathrm{K}$. The measurements revealed a clear transition from negative to positive as Eu content $x$ is increased room temperature. This related metal-insulator that occurs due disorder originated introduction of atoms it an Anderson transition. Our investigation found...
We investigated the photoconductivity effect in n-type PbTe/Pb0.88Eu0.12Te quantum wells for a temperature range of 300–10 K using infrared light. The measurements revealed that at high temperatures, photoresponse has small amplitude. As decreases to T ∼ 75 K, however, amplitude increases reaching maximum value 10 times higher than original before illumination. From Hall performed under dark and light conditions, we show this is result carrier concentration increase Unexpectedly, further...
In this work, we present the results of photoconductivity measurements performed in temperature range 12 K–300 K on a 150 nm-thick Bi2Te3 film grown by molecular beam epitaxy (111) BaF2 substrate. A transition from negative to positive is found occur around 125 K. Resistivity and Hall data measured under light dark conditions qualitatively elucidate observed phenomena. The Arrhenius plot recombination times obtained decay curves at different temperatures gives activation energy associated...