Essai sur la physiognomonie, destiné à faire connoître l'homme et à le faire aimer, par Jean Gaspar Lavater... [Physiognomische Fragmente zur Beförderung der Menschenkenntniss und Menschenliebe. Traduit de l'allemand par Mme de La Fite, M. M. Caillard et H. Renfner.]

Numérisation partielle de reliure

Essai sur la physiognomonie, destiné à faire connoître l'homme et à le faire aimer, par Jean Gaspar Lavater... [Physiognomische Fragmente zur Beförderung der Menschenkenntniss und Menschenliebe. Traduit de l'allemand par Mme de La Fite, M. M. Caillard et H. Renfner.]

Numérisation partielle de reliure

Essai sur la physiognomonie, destiné à faire connoître l'homme et à le faire aimer, par Jean Gaspar Lavater... [Physiognomische Fragmente zur Beförderung der Menschenkenntniss und Menschenliebe. Traduit de l'allemand par Mme de La Fite, M. M. Caillard et H. Renfner.]

Numérisation partielle de reliure

Essai sur la physiognomonie, destiné à faire connoître l'homme et à le faire aimer, par Jean Gaspar Lavater... [Physiognomische Fragmente zur Beförderung der Menschenkenntniss und Menschenliebe. Traduit de l'allemand par Mme de La Fite, M. M. Caillard et H. Renfner.]

Numérisation partielle de reliure

Reliure de : Discours politiques de messire Daniel de Priezac,... 1re [-2e] partie

Numérisation partielle de reliure

Bipolar pulsed excitation of erbium-doped nanosilicon light emitting diodes

High quantum efficiency erbium doped silicon nanocluster (Si-NC:Er) light emitting diodes (LEDs) were grown by low-pressure chemical vapor deposition (LPCVD) in a complementary metal-oxide-semiconductor (CMOS) line. Erbium (Er) excitation mechanisms under direct current (DC) and bipolar pulsed electrical injection were studied in a broad range of excitation voltages and frequencies. Under DC excitation, Fowler-Nordheim tunneling of electrons is mediated by Er-related trap states and electroluminescence originates from impact excitation of Er ions. When the bipolar pulsed electrical injection is used, the electron transport and Er excitation mechanism change. Sequential injection of electrons and holes into silicon nanoclusters takes place and nonradiative energy transfer to Er ions is observed. This mechanism occurs in a range of lower driving voltages than those observed in DC and injection frequencies higher than the Er emission rate.

Polarization strategies to improve the emission of a Si-based light source emitting at 1.55 um

We present a electroluminescence (EL) study of the Si-rich silicon oxide (SRSO) LEDs with and without Er3+ ions under different polarization schemes: direct current (DC) and pulsed voltage (PV). The power efficiency of the devices and their main optical limitations are presented. We show that under PV polarization scheme, the devices achieve one order of magnitude superior performance in comparison with DC. Time-resolved measurements have shown that this enhancement is met only for active layers in which annealing temperature is high enough (>1000 ◦C) for silicon nanocrystal (Si-nc) formation. Modeling of the system with rate equations has been done and excitation cross-sections for both Si-nc and Er3+ ions have been extracted.