Interface Chemistry and Energy Level Alignment of Silicon / Organic Semiconductor Heterostructures studied with Synchrotron Radiation X-ray Photoelectron Spectroscopy and Near Edge X-ray Absorption Fine Structure / Anzar Khaliq ; sous la direction de François Rochet

Date :

Editeur / Publisher : [S.l.] : [s.n.] , 2012

Type : Livre / Book

Type : Thèse / Thesis

Langue / Language : anglais / English

Rayonnement synchrotron

Silicium

Spectroscopie de photoélectrons

Spectroscopie d'absorption X -- Dissertation universitaire

Cyclopentanes -- Dissertation universitaire

Rochet, François (19..-.... ; professeur) (Directeur de thèse / thesis advisor)

Université Pierre et Marie Curie (Paris ; 1971-2017) (Organisme de soutenance / degree-grantor)

Relation : Interface Chemistry and Energy Level Alignment of Silicon / Organic Semiconductor Heterostructures studied with Synchrotron Radiation X-ray Photoelectron Spectroscopy and Near Edge X-ray Absorption Fine Structure / Anzar Khaliq ; sous la direction de François Rochet / Lille : Atelier national de reproduction des thèses , 2012

Résumé / Abstract : To date the most widely used inorganic semiconductor is silicon (Si). There is no denial to its contribution in the current standing of micro-electronics but with time its limitations have been exposed, especially the absence of coupling with opto-electronics due to its indirect band gap. Devices which consist of a hybrid of both organic (e.g. dyes) and Si are thought to be an interesting extension of the next generation Si-based devices. In this context, the modification of Si with organic molecules represents a promising approach for the incorporation of new functionalities into semiconductors (light harvesting, light emission). This has motivated the current research efforts on organic functionalization of the Si(001) surface, via a reaction of a functional group of the organic molecules with the dimers of the Si (001)– 2×1 surface. However, many interesting molecular objects grafted directly on semiconductor surface are multifunctional, which in most cases leads to competitive reactions with the surface silicon atoms and to multiple adsorption geometries. We have tackled this problem by passivating the silicon surface with cyclopentene (C5H8). The passivated layer has then been used as the substrate to grow molecular layers of TCNQ, (Tetracyanoquinodimethane) and PTCDA (3,4,9,10-perylene tetra carbonyl dianhydride). X-ray Photoelectron Spectroscopy (XPS) and Near Edge X-ray Absorption Fine Structure Spectroscopy (NEXAFS) have been used to determine the precise adsorption geometry of the buffer layer along with the molecular orientation of the adsorbate. Using the same techniques, the chemical environment of the organic / inorganic heterostructure interface has been studied in detail (PTCDA-cyclopentene / Si(001), TCNQ-cyclopentene / Si(001)) along with the molecular orientation (as function of film thickness) and the variations in band alignment. The latter studies may open new avenues in the development of these heterostructures in which modified silicon surfaces could be used as charge injecting / blocking electrodes.