Enhancement of erbium photoluminescence by substitutional C alloying of Si

Abstract

Photoluminescence (PL) at 1.54 μm of erbium-doped Si1−yCy alloys grown by molecular beam epitaxy (MBE) has been analyzed depending on sample temperature, excitation density, and growth conditions. Erbium activation raises with increasing incorporation of substitutional carbon compared to interstitial carbon. For [Er]=4.5×1019 cm−3 and y=0.1% maximum PL output at 1.54 μm was achieved for growth temperatures at 430 °C. Additional annealing could further enhance PL intensity at 1.54 μm. For increasing sample temperature a decrease of PL intensity with two characteristic activation energies around 100 and 10–20 meV is observed, which results in quenching of PL intensity at lower temperatures for Si:Er:C layers compared to Si:Er:O layers. PL spectra show different fine structure for oxygen and carbon codoping by MBE or ion implantation, higher efficiency, and lower PL background for MBE-grown samples in contrast to ion-implanted layers.

Enhancing effect of tensile strain on photoluminescence of Er in Si on a SiGe layer

“…Oxygen codoping enhances both solubility [1] and the optical activation of Er in Si [2]. The effects of impurity codoping on the luminescence of Er in Si have been studied to improve the luminescence properties [2][3][4][5][6][7][8]. On the other hand, the photoluminescence (PL) and electroluminescence (EL) of Er-doped SiGe have been also studied because of the refractive index of a SiGe layer increased as compared with bulk Si [9][10][11][12][13][14].…”

Excitation efficiency of electrons and holes in forward and reverse biased epitaxially grown Er-doped Si diodes

“…Temperature dependent PL measurements indicate that the exciton, that transfers its energy by an Auger process to the erbium ion, is bound to a conduction band related donor level. 2,7,8 In the p region of a diode enough holes are available to form an exciton with the electron localized at the donor level correlated with the erbium a͒ Author to whom correspondence should be addressed; electronic mail: markmann@wsi-tu-muenchen.de ion, whereas in the n region a lack of holes exists. This may result in the reduced EL output at 1.54 m for erbium in the n-doped layer of the forward biased diodes.…”

“…[1][2][3][4][5] Additional codopants allow to incorporate erbium ions up to concentrations of 10 20 cm Ϫ3 without significant segregation and enhance the number of the optical active erbium centers. 1,2 The erbium ion in the silicon host can be excited in two ways: On the one hand, erbium in combination with a codopant introduces an impurity level in the silicon band gap. Excitons can be bound at this impurity level and transfer their energy by an Auger process to the 4 f shell of the erbium ion promoting an electron from the 4 I 15/2 to the 4 I 13/2 level.…”

Nd3+ photoluminescence and its implication on the excitation mechanisms of Nd3+ in Nd doped hydrogenated amorphous silicon alloyed with carbon

“…Finally, the 1.1 lm emission results from a four level energy transition, and therefore facilitates achieving population inversion. a-Si:H:C was chosen because carbon co-doping is well-known to enhance the Er 3+ luminescence in Si [19,20] without serious degradation of the electronic properties of the film [20,21]. We observe clear luminescence peaks at 0.92, 1.11, and 1.40 lm corresponding to 4 F 3/2 !…”