Optical properties of Si-Si1−xGex and Si-Ge nanostructures

Abstract

This paper reviews the current research status on the optical properties of Si-Sil _×Ge× and Si-Ge nanostructures. Although this is a relatively new field, existing research has already achieved promising results in terms of both physics and possible device applications including the effect of process-induced strain in nanostructures, quantum confinement and improved optical efficiency of collective excitation in wires with reduced dimension, and especiallythe huge improvement of optical efficiency in quantum dots after nanofabrication.These results potentially open a new field of research into both the physics of Si-Sil-×Gex nanostructures and the possible applications of them in cheap Si based optoelectronic industry.

Room temperature electroluminescence of nanofabricated Si–Si1−xGexquantum dot diodes

“…When the superlattice was cut into 50 nm of quantum dots, the TO phonon-assisted EL peak disappeared, the dominant peak narrowed significantly and the intensity of the dominant peak increased by over two orders of magnitude higher than corresponding as-grown superlattice diode. These results are similar to those observed in the photoluminescence (PL) of similarly fabricated quantum dots [8,9].…”

“…However, there are still no convincing experimental results which unambiguously proved the existence of such a direct bandgap [5,6]. Over the last five years, we have been investigating the optical properties of Si-SiGe quantum wires and dots [7,8] with very promising results, such as the observation of improved light emission efficiency by over two orders of magnitude in dry etched Si-SiGe quantum dots of less than 100 nm or so [9]. Although the physical origin of the enhanced light emission phenomenon is still to be understood, we have demonstrated electroluminescence of an array of 0749-6036/96/080505 + 07 $25.00/0 c 1996 Academic Press Limited quantum dot diodes at room temperature [10,11].…”

Three-dimensional compositional analysis of quantum dots

“…Progress in nano-structure technology has resulted in the production of self-organized structures, such as self-assembled quantum dots [1], which are of considerable interest to applications in opto-electronic devices. The semiconductor systems most well known to undergo self-organized growth are SiGe/Si and InGaAs/GaAs.…”

Structural, Compositional and Optical Properties of Self-Organised Ge Quantum Dots

“…Development of an efficient Si based light emitting material would make it possible to combine both optical and electronic components on the same Si substrate. Various methods of fabricating Ge quantum dots on Si substrates have been studied [3] but here we are concerned only with self organised quantum dots grown by molecular beam epitaxy (MBE). Two types of quantum dots have been commonly reported [4]: small pyramidal dots and larger domes.…”