Optical and Structural Characterization of Pin Photodetector Based on Germanium Nanocrystals for Third Generation Solar Cells

We investigated the structural and optoelectronic properties of p-n germanium nanocrystals based junctions embedded between GaAs substrate and layers of ZnO:Al or a-Si:H. Scanning electron microscopy and scanning tunneling microscopy were used on these junctions in this work. Calculations of tunneling current on the substrate showed effect of localized defects trapping Fermi level at the surface tending to make a semi-insulating substrate. The average value of the diameter of the Ge nanoparticle is around 12.5 nm. These results lay the foundation for the development of solar cells which active part is made of GeNCs

Optical and Structural Characterization of Pin Photodetector Based on Germanium Nanocrystals for Third Generation Solar Cells

We investigated the structural and optoelectronic properties of p-n germanium nanocrystals based junctions embedded between GaAs substrate and layers of ZnO:Al or a-Si:H. Scanning electron microscopy and scanning tunneling microscopy were used on these junctions in this work. Calculations of tunneling current on the substrate showed effect of localized defects trapping Fermi level at the surface tending to make a semi-insulating substrate. The average value of the diameter of the Ge nanoparticle is around 12.5 nm. These results lay the foundation for the development of solar cells which active part is made of GeNCs

Évaluation du courant d’obscurité des couches actives de photodétecteurs à base de GaAs

La connaissance du courant d’obscurité dans les photodétecteurs permet d’envisager une amélioration de leurs performances optiques et électriques. Dans l’optique d’optimiser la sensibilité spectrale de ces photodétecteurs, il urge d’évaluer le courant d’obscurité afin de le minimiser et pour assurer la stabilité des caractéristiques en fonctionnement. La mesure du courant d’obscurité est effectuée à température ambiante sur le GaAs dont la croissance a été réalisée à basses températures (GaAsBT) et sur le n- GaAs pour démontrer les caractéristiques électriques. Les mesures sur le courant d’obscurité ont montré l’influence de la température de recuit sur l’amplitude de courant. Les asymétries observées seraient dues à la qualité technologique des interfaces.Mots clés: GaAs, LT-GaAs, courant d’obscurité, photodétecteurs pinEnglish Title: Evaluation of dark current from active layers of photodetectors based on GaAsEnglish AbstractKnowledge of dark current in photodetector allows improving their optical and electrical performance. In order to optimize the spectral sensitivity of photodetectors, it is urgent to evaluate dark current in order to minimize and to ensure the stability of their characteristics in operation. Measurement of dark current is carried out at ambient temperature on GaAs grown at low temperatures (LT-GaAs) and on n-GaAs for demonstrating electrical characteristics. Measurements on the dark current have shown the influence of the annealing temperature on the current amplitude. The observed asymmetry could be due to the technological quality of interfaces.Keywords: GaAs, LT-GaAs, dark current, pin photodetecto

Tunneling spectroscopy of p-type doping in silicon from boron-containing molecular monolayer

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