Properties of Al2O3: nc-Si nanostructures formed by implantation of silicon ions into sapphire and amorphous films of aluminum oxide

Peculiarities of the formation and properties of light-emitting structures based on ion-synthesized silicon nanocrystals in SiO2 and Al2O3 matrices

“…After the implantation of silicon into the crystalline Al 2 O 3 (sapphire) matrix, such photoluminescence does not occur, even though the Si nanocrystals are formed (which was previously confirmed by high res olution electron microscopy) [11]. In the case of Al 2 O 3 films, a favorable effect on the photoluminescence of the Si nanocrystals is exerted by the SiO 2 shells formed around the nanocrystals [11] and damping the stresses which prevent the manifestation of luminescent prop erties of the nanocrystals in sapphire because of the breaking of interfacial interatomic bonds, i.e., the for mation of nonradiative recombination centers.…”

“…At the same time, the film variant of the Al 2 O 3 : NC Si system exhibits a characteristic photoluminescence in the near infrared (IR) spectral region, which is associ ated, in particular, with the possibility of oxidizing the surface of Si nanocrystals [12]. In our previous work [11], we have suggested that it is the formation of SiO x shells around nanocrystals that provides relaxation of stresses and photoluminescence in the Si nanocrystals ion synthesized in the initially amorphous Al 2 O 3 films. In order to verify this suggestion, it is reasonable to draw a parallel with the case of Si nanocrystals in SiO 2 films by means of a comparative analysis of the structure of Si nanocrystals and the nature of photolu minescence using the same methods, as well as to investigate the influence of the oxidation of the silicon nanocrystals when the oxidation process is controlled by varying the conditions (atmosphere) of annealing.…”

“…The stresses, which bring about the breaking of chem ical bonds and the generation of nonradiative recom bination centers, can be responsible for the absence of typical photoluminescence (in the wavelength range 650-900 nm) of Si nanocrystals formed in the crystal line Al 2 O 3 (sapphire) matrix [10,11]. At the same time, the film variant of the Al 2 O 3 : NC Si system exhibits a characteristic photoluminescence in the near infrared (IR) spectral region, which is associ ated, in particular, with the possibility of oxidizing the surface of Si nanocrystals [12].…”

Influence of the dielectric matrix on photoluminescence and energy exchange in ensembles of silicon nanocrystals

“…Dielectrics with high ε can be used as subgate dielectrics in multilayer struc tures with Si nanocrystals [4] or in memory elements based on Si quantum dots [5]. In addition, they are regarded as dielectrics that can be used instead of SiO 2 in light emitting diodes based on Si nanocrystals [2,3].…”

“…In addition to the classical, well studied system SiO 2 :nc Si, Si nanocrystals were obtained by various methods in Si 3 N 4 matrices [1] and in promising dielectric matrices with high static permittivity ε, namely, Al 2 O 3 [2] and ZrO 2 [3]. Dielectrics with high ε can be used as subgate dielectrics in multilayer struc tures with Si nanocrystals [4] or in memory elements based on Si quantum dots [5].…”