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Title: Optical characterizations of doped silicon nanocrystals grown by co-implantation of Si and dopants in SiO₂

Co-implantation, with overlapping implantation projected ranges, of Si and doping species (P, As, and B) followed by a thermal annealing step is a viable route to form doped Si nanocrystals (NCs) embedded in silica (SiO₂). In this paper, we investigate optical characterizations of both doped and un-doped Si-NCs prepared by this method. The effective NC presence in the oxide layer and their crystallinity is verified by Raman spectrometry. Photoluminescence (PL) and PL excitation measurements reveal quantum confinement effects and a gradual PL quenching with increasing dopant concentrations. In un-doped NC, the measured Stokes shift remains constant and its value ~0.2 eV is almost twice the Si–O vibration energy. This suggests that a possible radiative recombination path is a fundamental transition assisted by a local phonon. PL lifetime investigations show that PL time-decays follow a stretched exponential. Using a statistical model for luminescence quenching, a typical NC diameter close to 2 nm is obtained for As- and P-doped samples, consistent with our previous atomic probe tomography (APT) analyses. APT also demonstrated that n-type dopant (P and As) are efficiently introduced in the NC core, whereas p-type dopant (B) are located at the NC/SiO₂ interface. This last observation could explain the failuremore » of the luminescence-quenching model to determine NC size in B-doped samples. All together, these experimental observations question on possible different carrier recombination paths in P or As doped NC compared to B one's.« less
Authors:
; ; ;  [1]
  1. ICube Laboratory, Université de Strasbourg and CNRS, 23 rue du Loess, BP 20, F - 67037 Strasbourg cedex 2 (France)
Publication Date:
OSTI Identifier:
22305783
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 14; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANNEALING; ARSENIC ADDITIONS; BORON ADDITIONS; CARRIERS; DOPED MATERIALS; EXCITATION; INTERFACES; LAYERS; LIFETIME; NANOMATERIALS; NANOSTRUCTURES; PHOSPHORUS ADDITIONS; PHOTOLUMINESCENCE; RAMAN SPECTROSCOPY; RECOMBINATION; SILICON; SILICON OXIDES; TOMOGRAPHY