Karen L. Moore

ROOM-TEMPERATURE PHOTOLUMINESCENCE AND ELECTROLUMINESCENCE FROM ER-DOPED SILICON-RICH SILICON OXIDE

Porous silicon was doped by Er ions using electroplating and was converted to silicon-rich silicon oxide (SRSO) by partial thermal oxidation at 900 °C. The room-temperature photoluminescence (PL) at ∼1.5 μm is intense and narrow (⩽15 meV) and decreases by less than 50% from 12 to 300 K. The PL spectrum reveals no luminescence bands related to Si-bandedge recombination, point defects, or dislocations and shows that the Er3+ centers are the most efficient radiative recombination centers. A light-emitting diode (LED) with an active layer made of Er-doped SRSO (SRSO:Er) was manufactured and room temperature electroluminescence at ∼1.5 μm was demonstrated.

A Si‐based light‐emitting diode with room‐temperature electroluminescence at 1.1 eV

We have achieved room‐temperature electroluminescence (EL) at 1.1 eV from a light‐emitting diode with an active layer prepared by high‐temperature partial oxidation of electrochemically etched crystalline silicon. The EL is easily measurable under a forward bias ≥ 1 V and a current density <10 mA/cm2 and is only weakly temperature dependent from 12 to 300 K. The luminescence is due to Si band edge radiative recombination and originates from large silicon clusters within a nonstoichiometric silicon‐rich silicon oxide matrix.

Radiative isoelectronic complexes introduced during the growth of Si and Si1−xGex/Si superlattices by molecular beam epitaxy

Radiative isoelectronic impurity complexes consisting of pairs of Be atoms that bind excitons can be formed in both Si and SiGe/Si superlattices during growth by molecular beam epitaxy. We describe in this letter the conditions under which these radiative complexes can be formed, show that they can be localized in the alloy layers of a superlattice, and demonstrate that the blueshift of the bound‐exciton’s no‐phonon line that occurs for Be‐implanted superlattices is absent for grown‐in Be complexes. Be densities in excess of 5×1017 cm−3 can be achieved.

Room Temperature Band-Edge Luminescence from Silicon Grains Prepared by the Recrystallization of Mesoporous Silicon

Room-temperature photoluminescence (PL) peaking at 1.1 eV has been found in electrochemically etched mesoporous silicon annealed at 950°C. Low-temperature PL spectra clearly show a fine structure related to phonon-assisted transitions in pure crystalline silicon (c-Si) and the absence of defect-related (e.g.P-line) and impurity-related (e.g.oxygen, boron) transitions. The maximum PL external quantum efficiency (EQE) is found to be better than 0.1% with a weak temperature dependence in the region from 12K to 400K. The PL intensity is a linear function of excitation intensity up to 100 W/cm 2 . The PL can be suppressed by an external electric field ≥ 10 5 V/cm. Room temperature electroluminescence (EL) related to the c-Si band-edge is also demonstrated under an applied bias ≤ 1.2 V and with a current density ≈ 20 mA/cm 2 . A model is proposed in which the radiative recombination originates from recrystallized Si grains within a non-stoichiometric Si-rich silicon oxide (SRSO) matrix.