Light emission and charge trapping in Er-doped silicon dioxide films containing silicon nanocrystals

Abstract

The processes of electro- (EL) and photoluminescence (PL) and charge trapping in Er-implanted SiO2 containing silicon nanoclusters have been studied. It is shown that in Er-doped SiO2 with an excess of silicon nanoclusters of 10 at. %, a strong energy transfer from silicon nanoclusters results in a ten-fold increase of the PL peak at 1540 nm from Er luminescent centers, whereas the EL is strongly quenched by the excess silicon nanoclusters. It is further shown that the implantation of Er creates in the oxide positive charge traps with a giant cross section (σh0>10−13cm2). Introducing subsequent silicon nanocrystals in the oxide leads to the formation of negative charge traps of a giant cross section (σe0>10−13cm2). The possible reason for the EL quenching in the Er-doped SiO2 by silicon nanoclusters is discussed.

Bipolar pulsed excitation of erbium-doped nanosilicon light emitting diodes

“…20 The Er-doped device is less conductive than the undoped device, which we ascribe to charge trapping at deep energy levels due to Er ion implantation. 21 This is also supported by the C-V measurements (Fig. 2).…”

Current transport and electroluminescence mechanisms in thin SiO2 films containing Si nanocluster-sensitized erbium ions

“…8 Because Si-ncls are capable of efficient energy transfer to erbium and other rare earth ions, silicon-rich erbiumdoped silica as a material for EL devices became a subject of research. [9][10][11] However, the role of the Si-ncls in the EL of Er and conduction mechanisms is not clear. It is agreed that the presence of Si-ncls introduces more efficient conduction mechanisms, including variable range hopping, 12 direct tunneling ͑DT͒, trap-assisted tunneling, Poole-Frenkel ͑PF͒ conduction, 13 or space charged limited current ͑SCLC͒.…”

“…11 Si nanoparticles favor the injection of charge carriers, improve device lifetime, 14 reduce the population of hot electrons, 15 and consequently reduce impact excitation of Er. 10,16 It has also been argued that other mechanisms of EL can be introduced, including energy transfer from electrically excited Sincls to erbium ions. 13 In general, different processes can be dominant depending on material composition, film thickness, or voltage regimes.…”

Bright green electroluminescence from Tb3+ in silicon metal-oxide-semiconductor devices

“…The most prominent systems are porous silicon, 5 silicon nanocrystals in SiO 2 , 6 p-n diodes, 7,8 Ge + -implanted SiO 2 , 9 and Er-doped silicon-rich SiO 2 sensitized with silicon nanocrystals. 10,11 The latter ones, realized as metal-oxide-semiconductor ͑MOS͒ light emitters, are especially attractive, since they are fully compatible with silicon complementary metal-oxidesemiconductor ͑CMOS͒ technology. Efficient MOS EL devices have been fabricated by erbium-doped silicon-rich SiO 2 with the attractive infrared light emission at 1.54 m for telecommunications.…”