Manganese (Mn) doped III-V dilute ferromagnetic semiconductors (DFSs) are a candidate materials for semiconductor spintronics due to their intrinsic ferromagnetism mediated by holes. In this thesis, Mn doped III-V dilute ferromagnetic semiconductors (DFSs), including (Ga,Mn)As, (In,Mn)As, (Ga,Mn)P, and (In,Ga,Mn)As have been successfully prepared by ion implantation and pulsed laser melting. All (In,Ga,Mn)As films are confirmed to be well recrystallized and ferromagnetic while their Curie temperatures depend on the Ga concentration. (Ga,Mn)As and (Ga,Mn)P have an inplane easy axis, while an out-of-plane easy axis for (In,Mn)As is observed. However, all of them do not present strong in-plane uniaxial anisotropy between [110] and [110] directions, which always occurs in low temperature molecular beam epitaxy (LT-MBE) grown (Ga,Mn)As samples. The reason is ascribed to the fact that the ultra-fastrecrystallization induced by pulsed laser melting weakens the formation of Mn-Mn dimers along the [100] direction which occurs in LT-MBE grown (Ga,Mn)As. Then selected samples were co-doped with Zn or irradiated with He ions. The Zn co-doping leads to the increase of conductivity of (Ga,Mn)P, however both the Curie temperature and magnetization decrease, which is probably due to the suppression of active Mn substitution by Zn co-doping. By using Rutherford Backscattering Spectroscopy and Particle-Induced X-ray Emission, the substitutional Mn atoms in (Ga,Mn)As are observed to shift to interstitial sites, while more Zn atoms occupy Ga sites. This is consistent with first-principles calculations, showing that the formation energy of substitutional Zn and interstitial Mn is 0.7 eV lower than that of interstitial Zn and substitutional Mn. For ion irradiated (Ga,Mn)As, (In,Mn)As and (Ga,Mn)P, both Curie temperature and magnetization decrease due to the hole compensation. However, the compensation effect is the strongest in (In,Mn)As and the least in (Ga,Mn)P. This is due to the different energy level of the produced defect relative to the band edges in different semiconductors. The results in the thesis point to an important issue: the difference in the band alignment and the hole binding energy of Mn dopants in different III-Mn-V dilute ferromagnetic semiconductors have strong influence on their magnetic properties and should be taken into account in the material design.

Hochaufgelöste räumlich-selektive Einzelionenimplantation ist eine Schlüsseltechnologie um Festkörper-Qubits herzustellen. Der in dieser Arbeit verwendete Nanoimplanter benutzt zur Kollimation eines niederenergetischen Ionenstrahls auf Nanometerebene eine Rasterkraftmikroskop-(AFM-)Spitze, welche mit einer Nanoapertur ausgestattet ist. Diese Technik wurde bereits für verschiedene Quantenanwendungen genutzt. In dieser Arbeit wird sie auf die Erzeugung strukturierter Stickstoff-Fehlstellen-(NV-)Zentren weiterentwickelt und optimiert. Dies umfasst unter anderem die Installation eines neuen AFM-Systems, welches den Aufbau mit zwei nützlichen Funktionen aufrüstet: die In-situ-Aperturvermessung und die Untersuchung von Ionen-sensitiven Fotolacken. Weiter werden die zwei wichtigsten limitierenden Faktoren der räumlichen Auflösung durch Simulationen und Experimente detailliert untersucht. Die Ergebnisse geben Aufschluss über optimale Nanoaperturen und Implantationsbedingungen. Streueffekte an der AFM-Spitze und Gitterführungen in Diamant können dadurch maßgeblich reduziert werden. Weiter werden NV-limitierende Effekte durch mehrere Ausheizschritte sowie Ionen- und Elektronenbestrahlungen untersucht. Zuletzt werden erstmals diamantbasierte Ionendetektoren hergestellt, welche mit Kapazität- und Strom-Spannungs-Messungen, durch Röntgenbestrahlung und Ionenstrahl-induzierter Ladung (IBIC) charakterisiert werden. Die Ergebnisse zeigen, dass die angefertigten Detektoren die Bedingungen für eine deterministische Implantation erfüllen, so dass dieses Prinzip zukünftig in den Nanoimplanter integriert werden kann. / High-resolution spatial-selective single ion implantation is a key technology to produce solid state qubits. The nanoimplanter used in this work collimates a low-energy ion beam at the nanometer level using an atomic force microscope (AFM) tip, which is provided with a nanoaperture. This technique has already been used for various quantum applications. In this thesis it is further developed and optimized for the generation of structured nitrogen vacancy (NV) centers. This includes the installation of a new AFM system, which upgrades the setup with two useful functions: in-situ aperture measurement and the investigation of ion sensitive photoresists. Furthermore, the two most significant limiting factors of spatial resolution are studied in detail by simulations and experiments. The results indicate optimized nanoapertures and implantation conditions. Scattering effects at the AFM tip and ion channeling in diamond can be significantly reduced. Moreover, NV-limiting effects are investigated by several heating steps as well as ion and electron irradiations. Finally, novel diamond based ion detectors are manufactured, that are characterized by capacitance and current-voltage measurements, by X-ray irradiation and ion beam induced charge (IBIC). The results show these detectors fulfill the conditions for a deterministic implantation, so that this concept can be integrated into the nanoimplanter in the future.

We report on the systematic characterization of the optical properties of diamond color centers based on Pb impurities. An ensemble photoluminescence analysis of their spectral emission was performed at different excitation wavelengths in the 405–520 nm range and at different temperatures in the 4–300 K range. The series of observed spectral features consist of different emission lines associated with Pb-related defects. Finally, a room-temperature investigation of single-photon emitters under 490.5 nm laser excitation is reported, revealing different spectral signatures with respect to those already reported under 514 nm excitation. This work represents a substantial progress with respect to previous studies on Pb-related color centers, both in the attribution of an articulated series of spectral features and in the understanding of the formation process of this type of defect, thus clarifying the potential of this system for high-impact applications in quantum technologies.

<p>We propose a physically based model that describes the density and size of voids in silicon introduced via high dose helium ion implantation and subsequent annealing. The model takes into account interactions between vacancies, interstitials, small vacancy clusters, and voids. Void evolution in silicon occurs mainly by a migration and coalescence process. Various factors such as implantation energy and dose, anneal temperature, atmospheric pressure, and impurity level in silicon can influence the migration and coalescence mechanism and thus play a role in the void evolution process. Values for model parameters are consistent with known values for point defect parameters and assumed diffusion limited reaction rates. A single “fitting parameter” represents the rate of bubble migration and coalescence and is therefore related to surface diffusion of adatoms. Results obtained from simulations based upon the model were compared to our experimental results and to previously reported experimental results obtained over a wide range of conditions.</p> <p>Our own experiments involved the implantation of silicon samples and samples with a thin Si_1-xGe_x (x = 0.05, 0.09) epilayer on silicon with 30 keV, 5×10¹⁶ cm^-2 helium. Anneals were done in the range 960-1110°C for 15-30 minutes in nitrogen and dry oxygen. Void size distributions were measured from transmission electron microscopy images. Average void diameter and void density values and void size distribution did not show any significant differences between the samples annealed in nitrogen and dry oxygen. However, the presence of Si_1-xGe_x epilayer on silicon resulted in increased average void diameter and reduced average void density when compared with Si samples as well as more selective void size distribution.</p> <p>Data from the literature included experiments with helium ion implantation energies in the range 30 - 300 keV, doses of 1×10¹⁶ - 1×10¹⁷ cm^-2, subsequent annealing temperatures in the range 700 - 1200°C, and annealing duration in the range 15 minutes - 2 hours. Excellent agreement is found between the simulated results and those from reported experiments. The extracted migration and coalescence rate parameter shows an activation energy consistent with surface diffusivity of silicon. It shows a linear dependence on helium dose, and increases with decreased implantation energy, decreased ambient pressure, decreased substrate impurities, increased temperature ramp rate, or increased Ge fraction in cavity layer, all consistent with the proposed physical mechanism. Our mathematical model specifically ignores the long time saturation in void size, although we propose a simple explanation consistent with the physical picture. Similarly, we give physical reasons for a threshold implant dose resulting in the formation of small vacancy clusters during implant. But in modeling void growth we simply show that when such clusters exist voids will evolve according to our model.</p> <p>In our experiments, the presence of a Si_0.95Ge_0.05 epilayer on silicon resulted in retarded B diffusion when compared with Si samples. This phenomenon is correlated to the role of the Si_0.95Ge_0.05 epilayer on silicon in the void evolution mechanism and both are attributed to Ge interdiffusing from the epilayer into the Si bulk. The B diffusion data also allows us to predict conditions for the SiGe epilayer to modify the injection of interstitials from surface during dry oxidizing anneal.</p> / Doctor of Philosophy (PhD)

Die vorliegende Arbeit beschäftigt sich mit den Auswirkungen der Ionenimplantation auf die Materialeigenschaften verschiedener magnetischer Probensysteme. Durch die Implantation mit Ionen kann man auf vielfältige Art und Weise die Eigenschaften von magnetischen Materialien modifizieren und maßschneidern, so zum Beispiel die Sättigungsmagnetisierung und die magnetische Anisotropie. Aus der Untersuchung von drei verschiedenen Probensystemen ergibt sich die Dreigliederung des Ergebnisteils. Im ersten Teil der Arbeit, dem Hauptteil, wird die Strukturierung von Permalloyschichten durch Ionen und der Einfluss auf den anisotropen Magnetowiderstand (AMR) untersucht. Der AMR ist direkt abhängig von der Ausrichtung der Magnetisierung eines Materials zum angelegten Strom. Um die Magnetisierungsrichtung sichtbar zu machen wurde ein Kerrmikroskop benutzt. Dieses wurde im Rahmen dieser Arbeit technisch erweitert um gleichzeitig auch den AMR messen zu können. Damit war es erstmalig möglich den AMR und die magnetischen Domänenkonfigurationen direkt zu vergleichen. Durch eine weitere Modifikation des Kerrmikrosops ist es möglich quantitative Bilder eines kompletten Ummagnetisierungsvorganges zu messen. Es konnte gezeigt werden, dass der berechnete AMR des Bildausschnittes mit dem gemessenen übereinstimmt. Der AMR ist abhängig von der Streifenbreite, der Streifenausrichtung zum Strom, der Stärke der induzierten Anisotropie, dem angelegten Feldwinkel und der Sättigungsmagnetisierung. Im Fall von schmalen Streifen führt das zweistufige Schalten zu einem AMR-Maximum, wenn die Streifen mit der niedrigeren Sättigungsmagnetisierung geschaltet haben. Das Zusammensetzen der Streifenstruktur ermöglicht es den AMR gezielt zu manipulieren. Bei geringer induzierter Anisotropie sind verschiedene komplexe Domänen messbar, welche sich in einem asymmetrischen AMR widerspiegeln. So kann der AMR auf vielfältige Weise manipuliert und deren Abhängigkeit von den magnetischen Domänen mittels Kerrmikroskopie gemessen werden. Im zweiten Teil wurde die Erzeugung eines Anisotropiegradienten durch Ionenimplantation in einem Speichermedium untersucht. Hierbei handelt es sich um eine Kooperation mit Peter Greene (University of California Davis) und Elke Arenholz (Lawrence Berkeley Laboratory). Nachdem die Ionenverteilung in dem Material mit TRIDYN simuliert wurde, erfolgte eine Implantation in die oberen Schichten der Co/Pd Multilagen. Dieses hat eine Veränderung der magnetischen Anisotropie zur Folge. Die Ummagnetisierungskurven sind mit dem polaren magnetooptische Kerreffekt (polaren MOKE) und Vibrationsmagnetometrie vermessen worden. Außerdem fand eine Strukturanalyse mit Röntgenreflektrometrie und Röntgendiffraktometrie statt. Die abschließende Beurteilung des Schaltverhaltens erfolgte durch die Auswertung der Ummagnetisierungskurven erster Ordnung. Es ist uns gelungen die oberen Schichten durch die Implantation weichmagnetisch zu machen. Die darunterliegenden Schichten sind noch hartmagnetisch und das Material zeigt textit{exchange spring} Verhalten. Es erfüllt somit die Voraussetzungen, um als Speichermedium genutzt zu werden. Damit konnte erfolgreich gezeigt werden, dass man mit Ionenimplantation einen Anisotropiegradienten in einem Speichermedium erzeugen kann und dadurch das gewünschte Schaltverhalten erzeugt. Im dritten Teil, in einem Projekt mit Björn Obry (TU Kaiserslautern), geht es um die Erzeugung eines Spinwellenleiters und eines magnonischen Kristalls durch die Ionenimplantation in Permalloy. Zur Herstellung des Spinwellenleiters und des magnonischen Kristalls macht man sich die lokale Reduzierung der Sättigungsmagnetisierung durch die Implantation zu nutze. Es wurden Messungen mit dem polaren MOKE gemacht. Die Spinwellencharakterisierung ist mit dem Brillouin-Lichtstreumikroskop durchgeführt worden. Es war möglich die Ionenimplantation zur Herstellung eines magnonischen Kristalls und eines Spinwellenleiters zu nutzen. Das Verändern von magnetischen Materialeigenschaften durch Implantation eröffnet somit verschiedene Möglichkeiten. Mit Ionenimplantation kann man Permalloy so strukturieren, dass man den AMR gezielt manipulieren kann. Außerdem wurde Ionenimplantation genutzt um einen Anisotropiegradienten in einem Speichermedium zu erzeugen. Durch diesen Anisotropiegradient konnte das Schaltverhalten gezielt modifiziert werden. Mit Hilfe von Ionenimplantation kann man auch ein magnonisches Kristall und einen Spinwellenleiter herstellen. / This thesis deals with magnetic modification of ferromagnetic films by ion implantation, such as induced changes of the magnetic anisotropy and changes in the saturation magnetization. Three different sample structures were investigated. Therefore the result section is divided into three parts. The influence of ion induced magnetic patterning on the anisotropic magnetoresistance (AMR) is investigated in the first part. The AMR directly depends on the angle between the applied current and the magnetization of the material. To investigate this relationship a Kerr microscopy,for observing the magnetic domains was combined with resistance measurements. The measurements were performed on stripe patterned permalloy samples. This is the main part of the thesis. The creation of an anisotropy gradient in a storage media by ion implantation is the topic of the second part. It was a collaborative project with Peter Greene (University of California Davis) and Elke Arenholz (Lawrence Berkeley Laboratory). The goal was to create a magnetic anisotropy gradient by introducing ions in the upper layer of the Co/Pd- multilayer. After TRIDYN simulations of the ion distribution, the implantation was performed and the magnetization curves were measured with polar magneto-optical Kerr effect and vibrating sample magnetometry. In addition to this, structural characterization was carried out by x-ray reflection and x-ray diffraction measurements. For the final determination of the switching behavior first order reversal curves were analyzed. The aim of the third part was to create a spin wave guide and a magnonic crystal by local ion implantation. In this project with Björn Obry (TU Kaiserslautern) the characteristic of the ions to reduce the saturation magnetization in permalloy was used and the effect on the spin wave propagation was analyzed. Polar MOKE was performed to determine the saturation magnetization. Brillouin light scattering microscopy was used to analyze the spin wave behavior inside the material.

The objective of the research in this thesis is to develop manufacturable high-efficiency silicon solar cells at low-cost through advanced cell design and technological innovations using industrially feasible processes and equipment on commercial grade Czochralski (Cz) large-area (239 cm2) silicon wafers. This is accomplished by reducing both the electrical and optical losses in solar cells through fundamental understanding, applied research and demonstrating the success by fabricating large-area commercial ready cells with much higher efficiency than the traditional Si cells. By developing and integrating multiple efficiency enhancement features, namely low-cost high sheet resistance homogeneous emitter, optimized surface passivation, optimized rear reflector, back line contacts, and improved screen-printing with narrow grid lines, 20.8% efficient screen-printed PERC (passivated emitter and rear cell) solar cells were achieved on commercial grade 239 cm2 p-type Cz silicon wafers.

The radioactive ion implantation wear measuring method (RII) has been used for many years as a tool to make highly sensitive real-time in-situ measurements of wear and corrosion in metallic or ceramic materials. The method consists of the controlled implantation of radioactive ions of limited decay time in a thin layer at the surface of the material. The progressive abrasion of the material results in a decline in radioactivity which is followed to monitor material losses. The application of RII to control the wear of polymers is potentially of interest, but it has been lagging behind because of uncertainties related to possible changes in material properties during and after the implantation, and to the exact shape of implantation profiles. In this thesis, we investigate these issues on two thermoplastic elastomers typically used for making the soles of sport shoes, among which one contains radiation-sensitive unsaturated bonds, using as ions 7Be, 7Li and Kr. The results of the sample characterisation indicate that the 7Be and 7Li implantations, under properly-selected conditions, do not induce significant modifications in the materials. The implantation of a stack of polymer thin films and the activity measurements performed to determine the implantation profile are also presented. The experimental results on the ion implantation profiles and the determination of calibration curves are presented and discussed in comparison with simulated results. The results indicate that it is possible to predict the implantation profile by means of simulations. This bodes well for the application of the RII method to polymer materials. In the last part, an experimental study is presented regarding the possible redistribution of the implanted 7Be after implantation. Since very few existing experimental techniques are able to detect light elements implanted in polymer targets at fluences less or equal to 1012 cm-2, with implantation depths of a few µm, a new method is presented, which implies the use of plasma etching techniques in order to remove layers of polymers and measuring the remaining activity after each step. Our results indicate that a redistribution of the implanted ions takes place during the implantation process, resulting in a scrambling of the initial implantation profile. Nevertheless, provided a suitable methodology be used, wear measurements in polymers by using the RII method are still possible, as we propose in the thesis.

No description available.

Cette thèse est dédiée à l’étude des matériaux InMnP et GaMnP fabriqués par implantation ionique et recuit thermique. Plus précisément nous avons investigué la possibilité de former par implantation ionique des matériaux homogènes (alliages) de InMnP et GaMnP contenant de 1 à 5 % atomiques de Mn qui seraient en état ferromagnétique, pour des possibles applications dans la spintronique. Dans un premier chapitre introductif nous donnons les motivations de cette recherche et faisons une revue de la littérature sur ce sujet. Le deuxième chapitre décrit les principes de l’implantation ionique, qui est la technique utilisée pour la fabrication des échantillons. Les effets de l’énergie, fluence et direction du faisceau ionique sur le profil d’implantation et la formation des dommages seront mis en évidence. Aussi dans ce chapitre nous allons trouver des informations sur les substrats utilisés pour l’implantation. Les techniques expérimentales utilisées pour la caractérisation structurale, chimique et magnétique des échantillons, ainsi que leurs limitations sont présentées dans le troisième chapitre. Quelques principes théoriques du magnétisme nécessaires pour la compréhension des mesures magnétiques se retrouvent dans le chapitre 4. Le cinquième chapitre est dédié à l’étude de la morphologie et des propriétés magnétiques des substrats utilisés pour implantation et le sixième chapitre, à l’étude des échantillons implantés au Mn sans avoir subi un recuit thermique. Notamment nous allons voir dans ce chapitre que l’implantation de Mn à plus que 1016 ions/cm2 amorphise la partie implantée du matériau et le Mn implanté se dispose en profondeur sur un profil gaussien. De point de vue magnétique les atomes implantés se trouvent dans un état paramagnétique entre 5 et 300 K ayant le spin 5/2. Dans le chapitre 7 nous présentons les propriétés des échantillons recuits à basses températures. Nous allons voir que dans ces échantillons la couche implantée est polycristalline et les atomes de Mn sont toujours dans un état paramagnétique. Dans les chapitres 8 et 9, qui sont les plus volumineux, nous présentons les résultats des mesures sur les échantillons recuits à hautes températures : il s’agit d’InP et du GaP implantés au Mn, dans le chapitre 8 et d’InP co-implanté au Mn et au P, dans le chapitre 9. D’abord, dans le chapitre 8 nous allons voir que le recuit à hautes températures mène à une recristallisation épitaxiale du InMnP et du GaMnP; aussi la majorité des atomes de Mn se déplacent vers la surface à cause d’un effet de ségrégation. Dans les régions de la surface, concentrés en Mn, les mesures XRD et TEM identifient la formation de MnP et d’In cristallin. Les mesures magnétiques identifient aussi la présence de MnP ferromagnétique. De plus dans ces mesures on trouve qu’environ 60 % du Mn implanté est en état paramagnétique avec la valeur du spin réduite par rapport à celle trouvée dans les échantillons non-recuits. Dans les échantillons InP co-implantés au Mn et au P la recristallisation est seulement partielle mais l’effet de ségrégation du Mn à la surface est beaucoup réduit. Dans ce cas plus que 50 % du Mn forme des particules MnP et le restant est en état paramagnétique au spin 5/2, dilué dans la matrice de l’InP. Finalement dans le dernier chapitre, 10, nous présentons les conclusions principales auxquels nous sommes arrivés et discutons les résultats et leurs implications. / This thesis is dedicated to the study of InMnP and GaMnP materials fabricated by ion implantation and thermal annealing. More precisely we have investigated the possibility of forming by ion implantation homogeneous InMnP and GaMnP materials (alloys), containing up to 5 at. % of Mn, that would be in a ferromagnetic state for possible applications in spintronics. In the first introductive chapter we give the motivations for this research and briefly comment the literature existent on this subject. The second chapter describes the principles of ion implantation, which is the technique used for the fabrication of the samples. The effects of the energy, fluency and direction of the ion beam on the implantation profile and the formation of damages will be highlighted. Also in this chapter we shall find information concerning the semiconducting substrates used for the implantation. The experimental techniques used for the structural, chemical and magnetic characterisation of the samples, together with their limitations are discussed in the third chapter. Some theoretical principles of magnetism necessary for the understanding of the magnetic measurements are presented in chapter 4. The fifth chapter is dedicated to the study of the morphology and magnetic properties of the substrates used for implantation and the sixth chapter to the study of samples implanted with Mn without thermal annealing. In particular we’ll see in this chapter that Mn implantation at more then 1016 ions/cm2 makes amorphous the implanted layer and the Mn atoms are distributed in depth following a Gaussian profile. The implanted Mn atoms are in a paramagnetic state between 5 and 300 K having the spin value of 5/2. In chapter 7 we present the properties of samples annealed at low temperatures. We shall see that in these samples the implanted layer is polycristalline and the Mn atoms are still in a paramagnetic state. In the chapters 8 and 9 that contain most of the results of this thesis, we present the measurements on samples annealed at high temperatures: in chapter 8 one shall find results on InP and GaP implanted with Mn and in chapter 9 one shall see results on InP co-implanted with Mn and P. Firstly, in chapter 8 we’ll see that thermal annealing at high temperatures leads to an epitaxial recrystallization of InMnP and GaMnP. But most of the Mn atoms diffuse to the surface due to a segregation effect. In the regions at the surface, highly concentrated in Mn, the XRD and TEM measurement identify the formation of MnP and In crystalline. The magnetic measurements identify also the presence of ferromagnetic MnP. Moreover in these measurements one finds that 60 % of the implanted Mn is in a paramagnetic state with the spin value reduced with respect to that found in un-annealed samples. In the InP samples co-implanted with Mn and P we have only a partial recrystallization but, the effect of segregation of Mn at the surface is much reduced. In this case more than 50 % of the implanted Mn forms ferromagnetic MnP and the rest of it is diluted in InP, in a paramagnetic state with spin 5/2. Finally, in the last chapter 10 we present the principal conclusion that we have reached and discuss the results and their implications.

Le but de ce projet est d’étudier l’effet des défauts cristallins sur les propriétés optoélectroniques de photodétecteurs fabriqué à partir de « silicium noir », c’est-à-dire du silicium dopé et microstructuré par impulsions laser femtoseconde, ce qui lui donne une apparence noire mate caractéristique. Des échantillons de silicium noir ont été recuits puis implantés avec des ions ayant une énergie de 300 keV (Si+), 1500 keV (Si+) ou 2000 keV (H+). Trois fluences pour chaque énergie d’implantation ont été utilisées (1E11, 1E12, ou 1E13 ions/cm2) ce qui modifie le matériau en ajoutant des défauts cristallins à des profondeurs et concentrations variées. Neuf photodétecteurs ont été réalisés à partir de ces échantillons implantés, en plus d’un détecteur-contrôle (non-implanté). La courbe de courant-tension, la sensibilité spectrale et la réponse en fréquence ont été mesurées pour chaque détecteur afin de les comparer. Les détecteurs ont une relation de courant-tension presque ohmique, mais ceux implantés à plus haute fluence montrent une meilleure rectification. Les implantations ont eu pour effet, en général, d’augmenter la sensibilité des détecteurs. Par exemple, l’efficacité quantique externe passe de (0,069±0,001) % à 900 nm pour le détecteur-contrôle à (26,0±0,5) % pour le détecteur ayant reçu une fluence de 1E12 cm-2 d’ions de silicium de 1500 keV. Avec une tension appliquée de -0,50 V, la sensibilité est améliorée et certains détecteurs montrent un facteur de gain de photocourant supérieur à l’unité, ce qui implique un mécanisme de multiplication (avalanche ou photoconductivité). De même, la fréquence de coupure a été augmentée par l’implantation. Une technique purement optique a été mise à l’essai pour mesurer sans contacts la durée de vie effective des porteurs, dans le but d’observer une réduction de la durée de vie causée par les défauts. Utilisant le principe de la réflexion photo-induite résolue en fréquence, le montage n’a pas réuni toutes les conditions expérimentales nécessaires à la détection du signal. / The goal of this project is to study the effect of crystalline damage on the optoelectronic properties of photodetectors made from “black silicon” (i.e. femtosecond-laser microstructured silicon, which make it appear black). Black silicon samples were annealed then implanted with either 300 keV Si+, 1500 keV Si+ or 2000 keV H+ ions. The fluence used for the implantation was 1E11, 1E12 or 1E13 ion/cm2, resulting in nine different samples with a crystalline damage distribution of various depth and concentration. Photodetectors were fabricated on these samples, together with a control detector made from a non-implanted black silicon sample and then characterized. The I-V curves, spectral responsivities and frequency responses of the detectors were measured in short-circuit or under bias and compared. The detectors display an approximately ohmic behavior, but those implanted at a higher fluence show a slightly better current rectification. The implantation had a strong effect on the responsivity. The external quantum efficiency increased from (0.069 ± 0.001) % at 900 nm for the control detector up to (26.0 ± 0.5) % for the 1E12 cm-2, 1500 keV Si+ detector. With an applied bias of -0.50 V, the responsivity is increased and some detectors exhibit above unity photocurrent gain. Similarly, the cutoff frequencies of the implanted detectors are higher. A contactless experiment was attempted for the measurement of the effective carrier lifetime. The implantation damage was expected to reduce the carrier lifetime. The setup didn’t meet all experimental conditions required to detect the signal using frequency-domain photo-induced reflection.