An efficient room-temperature silicon-based light-emitting diode

Abstract

There is an urgent requirement for an optical emitter that is compatible with standard, silicon-based ultra-large-scale integration (ULSI) technology. Bulk silicon has an indirect energy bandgap and is therefore highly inefficient as a light source, necessitating the use of other materials for the optical emitters. However, the introduction of these materials is usually incompatible with the strict processing requirements of existing ULSI technologies. Moreover, as the length scale of the devices decreases, electrons will spend increasingly more of their time in the connections between components; this interconnectivity problem could restrict further increases in computer chip processing power and speed in as little as five years. Many efforts have therefore been directed, with varying degrees of success, to engineering silicon-based materials that are efficient light emitters. Here, we describe the fabrication, using standard silicon processing techniques, of a silicon light-emitting diode (LED) that operates efficiently at room temperature. Boron is implanted into silicon both as a dopant to form a p-n junction, as well as a means of introducing dislocation loops. The dislocation loops introduce a local strain field, which modifies the band structure and provides spatial confinement of the charge carriers. It is this spatial confinement which allows room-temperature electroluminescence at the band-edge. This device strategy is highly compatible with ULSI technology, as boron ion implantation is already used as a standard method for the fabrication of silicon devices.

Crystal field analysis of Dy and Tm implanted silicon for photonic and quantum technologies

“…Our effective charges are comparable with those previously reported: the effective charge in III-V compounds is 2-2.5 [43], the Mulliken charges of Si atoms in zeolites was found to be ~2.5 [44]. The axial asymmetry could be caused by our dislocation engineering technique which introduces a uniaxial strain field caused by dislocation loops aligned to the four non-parallel <111> lattice planes [1,45,46]. Another possibility is the formation of a complex, with axial asymmetry, by charge compensation of the RE 3+ by other defects such as vacancies or impurities.…”

“…Dislocation engineering by boron implantation can be used to inhibit non-radiative decay paths and allow band edge photoluminescence (PL) and electroluminescence (EL) from Si [1]. The same dislocation engineering technique, accompanied by rare-earth (RE) implantation can be used to obtain PL and EL at specific wavelengths determined by the RE optical transitions [2,3].…”

A study of electrical properties of dislocation engineered Si processed by ultrasound

“…[21][22][23]), however, no room temperature luminescence has been found. After the dislocation engineered Si light emitting diode was first fabricated [3] effect of additional doping with sulphur impurities was also studied [20]. Below we study effect of UST on electrical properties of the sulphur doped dislocation engineered Si.…”

“…Since the discovery [1][2][3] of luminescent feature, study of dislocation engineered (DE) Si is one of the interesting scientific topics. Distinct from bulk Si, luminescence intensity of DE Si is found to increase with increasing the temperature from low to T=300 K. Here the strain field around dislocations plays an important role.…”

Temperature dependence of electroluminescence from silicon p-i-n light-emitting diodes

“…Because of its importance in technology, numerous efforts have been devoted to get an efficient light emission in the wavelength range from visible to infrared regions of the spectrum from Si-based materials, such as porous Si, Si nanocrystal, dislocation engineered Si, erbium doped Si, SiGe, as well as ␤-FeSi 2 . 1- 6 Recently, light emission from bulk silicon diodes with dislocation loops 7 or silicon diodes fabricated on silicon-on-insulator substrate and with textured surface 8,9 was demonstrated. The enhancement of light emission at higher temperature was observed in the samples with dislocation loops, which was attributed to the spatial localization of the radiative carrier population decoupled from nonradiative recombination, 7 or to the binding of electronhole pairs to the boron doping spikes.…”