Visible photoluminescence and quantum confinement effects in amorphous Si/SiO2 multilayer structures

TEM studies of Ge nanocrystal formation in PECVD grown SiO2:Ge/SiO2multilayers

“…In the literature, Si nanocrystals in Si/SiO 2 multilayers were obtained by a lowpressure chemical vapour deposition (LPCVD) of thin silicon layers and atmospheric pressure chemical vapour deposition (APCVD) of SiO 2 layers followed by high-temperature thermal oxidation [20,21]. Molecular beam epitaxy [22] and electron beam deposition [23] have also been used. However, there is no report of Ge nanocrystal formation in SiO 2 multilayers in the literature.…”

Photoluminescence properties of SiNx/Si amorphous multilayer structures grown by plasma-enhanced chemical vapor deposition

“…Previous studies have demonstrated photoluminescence (PL) from crystalline or amorphous nc-Si sandwiched between layers of larger gap materials such as SiO 2 or SiN x [2][3][4][5][6]. The particular interest in the nc-Si/SiO 2 and nc-Si/SiN x multilayer structures or superlattices is due to the high control over the nc-Si layer thickness that can be achieved, which is one of the key requirements for controlling their photoluminecent properties and device applications [2].…”

“…The emission wavelengths reported for these superlattices after being subjected to annealing processes are mainly located in the near infrared (IR) and visible (650-800 nm) regions. Among the different mechanisms proposed for explaining the radiative recombination processes, the most accepted one is related to quantum confinement effects (QCE), in which the emission features depend strongly on the size of the nc-Si layers [5,6]. However, many features of the optical emission and properties of these materials, as well as the role of surface and/or interfaces between nc-Si and matrix are still controversial and need to be clarified.…”

Quantum confinement and band offsets in amorphous silicon quantum wells

“…Soon after the fabrication of the first amorphous QWs reports on the increase of the optical gap [2,[4][5][6][7][8], resonant tunneling [5,9], and the shift of the photoluminescence peak followed [10,11]. The observed effects were attributed to quantum confinement of charge carriers, often employing the quantum well model to fit the data.…”