On the environment of optically active Er in Si-electroluminescence devices

Abstract

We report sharp, atomlike electroluminescence spectra close to 1.54 μm from a low-dose (3.5×1018 cm−3) erbium-implanted silicon light-emitting diode operating under forward bias. The well-resolved Stark splitting identifies the isolated interstitial Er with cubic site symmetry as the source. The full width at half maximum of the most intense line is 0.5 nm. A comparison with a highly Er (5×1019 cm−3) and O (1×1020 cm−3) doped diode with a high doping gradient grown by molecular beam epitaxy and with Er-implanted silica is given with respect to fine structure and thermal quenching. The room-temperature emission of the highly Er and O doped diode is ascribed to Er containing silica precipitates within the c-Si matrix.

Er–O clustering and its influence on the lattice sites of Er in Si

“…This situation is characterized by isolated Er atoms in defect-rich surroundings . For the lowest doses used in our studies (4-6×10 12 cm -2 at 60 keV) we found already about 70% of Er close to tetrahedral interstitial sites (T) [13], with a mean displacement of 0.42 Å from the T site. As already remarked before [8,13,16], the displacement of 0.42 Å can also be interpreted as a mixture of several sites in the range 0 to ≈0.6 Å from the T sites.…”

“…An intermediate situation is suggested for typical processing conditions which are used to optimize the luminescence output of Er implanted CZ Si, such as described in Ref. [12] Er suggest three main structural stages, which are distinguished by the amount of remaining lattice damage and the possibilities for Er n O m complex formation. In the following we will discuss these three stages in comparison with the results of other techniques which have investigated Er implanted Si samples.…”

“…It can be regarded as proven that O forms complexes with Er which directly modify the structural, electrical and optical properties of Er [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. However, there is also strong evidence that, possibly apart from ErO complex formation, additional mechanisms exist how O enhances the Er luminescence yield [6,7].…”

Qualitative aspects of the entanglement in the three-level model with photonic crystals

“…From a material standpoint, it is possible to dope an existing photonic band gap material using ion beam implantation methods. For instance, it has recently been shown that Er 3+ ions implanted into bulk silicon exhibit sharp free-atom-like spectra [32,33].…”

Light emission from Er at the As-terminated Si(111) surface

“…1 In bulk Si the excitation of Er occurs by the transfer of energy from excess electrons and holes to the Er ion. Certain aspects of the atomic scale environment of optically active Er atoms have been determined by extended x-ray absorption fine structure measurements, 2,3 the study of the crystal-field splitting on photoluminescence spectra, 4 and by modifying the chemical environment of the Er with ion implantation of impurities. 5 The conclusion of these studies is that Er atoms must be coordinated with impurities, such as oxygen, to participate efficiently in the light emission process.…”