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Master's Dissertation
DOI
10.11606/D.43.1999.tde-30082004-142115
Document
Author
Full name
Tomás Erikson Lamas
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 1999
Supervisor
Committee
Quivy, Alain Andre (President)
Cotta, Mônica Alonso
Santos, Marina Amelia Pinto Viegas da Silveira
Title in Portuguese
Espectroscopia a Nível Atômico Usando um Microscópio de Tunelamento (STM)
Keywords in Portuguese
filmes finos
microscopia de tunelamento
passivação
pontos quânticos
semicondutores
Abstract in Portuguese
O objetivo principal deste trabalho foi adicionar novos módulos (tanto eletrônicos quanto computacionais) necessários para efetuar medidas espectroscópicas com o microscópio de tunelamento construído há alguns anos no Laboratório de Novos Materiais Semicondutores do Instituto de Física da USP. Para checar a performance do novo sistema implementado, foram realizadas medidas sobre materiais condutores (grafite e ouro). Visando a análise topográfica e espectroscópica de amostras semicondutoras dos grupos III-V, estudamos alguns métodos para a preparação destas superfícies. Dentre eles, a passivação foi capaz de fornecer os resultados mais significativos. Finalmente, curvas da corrente de tunelamento em função da tensão aplicada à junção foram adquiridas sobre amostras de GaAs e pontos quânticos de InAs crescidos pela técnica de epitaxia por feixe molecular (MBE).
Title in English
Spectroscopy at atomic level by using a scanning tuneling microscope (STM)
Keywords in English
passivation
quantum dots
scanning tuneling microscopy
semiconductors
thin films
Abstract in English
The goal of the present work was to upgrade the home-made Scanning Tunneling Microscope present in our group, adding the new hardware necessary to carry out spectroscopic measurements. A new software was also developed to control the new functions of the microscope. In order to check the performance of the whole system, several types of experiments where carried out on graphite and gold. A special care was taken to adequately prepare the samples of III-V semiconductors. The passivation of the sample yielded the best results both for topographic and spectroscopic measurements. Finally, I-V curves were taken on GaAs layers and InAs quantum dots grown by molecular beam epitaxy (MBE).
 
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tomas_stm.pdf (3.93 Mbytes)
Publishing Date
2004-10-05
 
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