Crystalline Ge quantum dots embedded in SiO₂matrix synthesized by plasma immersion ion implantation

Abstract

A new plasma process, i.e. a combination of plasma immersion ion implantation and deposition (PIII&D) and high power impulse magnetron sputtering (HiPIMS), was developed to implant non-gaseous ions into material surfaces. The new process has the great advantage that thin film deposition and non-gaseous ion implantation can be achieved in a single plasma chamber. In this study, Ge ions were successfully implanted into SiO(2) thin film, which resulted in uniformly and homogeneously distributed crystalline Ge quantum dots (Ge-QDs) embedded in a SiO(2) matrix even without a further annealing process. Broader areas of application of PIII&D technology are envisaged with this newly developed process.

Electronic properties of single Ge/Si quantum dot grown by ion beam sputtering deposition

“…Due to the confinement of carriers in three dimensions, semiconductor quantum dots (QDs) are endowed with many interesting physical properties, such as the quantum size effect, the phonon bottleneck effect, the quantum tunneling effect, the Coulomb blockade effect, and the quantum hall effect-properties that have made QDs the most promising of all candidates for developing novel electronic and optoelectronic devices [1][2][3][4][5]. At the same time, the carrier capture time in QDs is much shorter than that in general quantum wells and defects [6][7][8].…”

Matrix role in Ge nanoclusters embedded in Si3N4 or SiO2

“…3,4 Ge QDs gained a renewed scientific interest over Si QDs, thanks to lower fabrication temperatures, higher absorption coefficient, and larger exciton Bohr radius ($24 nm). [5][6][7][8][9][10] Actually, Ge QDs embedded in SiO 2 have been already used in high-efficiency light detection devices, 11 showing also good tunneling features in resonant tunneling diodes. 12 Even if Ge QDs seem promising candidates as light harvesters, the photon absorption mechanism needs to be further exploited, especially for what concerns the embedding matrix.…”

“…[5][6][7][8]12,[15][16][17][18] Since it was shown that the fabrication techniques 19 and undesired Ge-O interaction 9 can affect the optical properties, we induced the formation of Ge NCs by implanting Ge ions in Si 3 N 4 or SiO 2 matrices and annealing. Implant energy (100 keV) and fluences (2.9À9.6 Â 10 16 Ge ions/cm 2 ) were chosen to induce the NC precipitation within 90 nm from the surface.…”

Design of free patterns of nanocrystals with ad hoc features via templated dewetting

“…In order to overcome these limitations, it has been proposed to use nanocrystals (NCs) as charge storage elements embedded in the gate oxide of a field-effect transistor. [1][2][3][4][5][6] Various processes have been developed to elaborate silicon (Si) or germanium (Ge) NCs, including self-assembly, 7-9 precipitation, 10 ion implantation, [11][12][13][14] and annealing. [15][16][17] Si and Ge NCs for which the local physical properties govern their electronic response have recently been fabricated.…”