Electronic States of P Donors in Si Nanocrystals Embedded in Amorphous SiO2 Layer Studied by Electron Spin Resonance: Hydrogen Passivation Effects

Abstract

Si nanocrystals (SiNCs) embedded in formed amorphous SiO2 layer and P nanoscale doping have been investigated by electron spin resonance (ESR) measurements at low temperatures. Hydrogen atom treatment is found to be required to determine the proper doping effects and electronic states of doped donors and quasi-conduction electrons in SiNCs. The dependences of microwave power and temperature for the ESR hyperfine structure of isolated P donors indicate that the spin–lattice relaxation time T1 becomes longer with decreasing size of SiNCs. From the experimental results of donor concentration and temperature dependence, we propose a novel model that the spin property of SiNCs of approximately 5.8 nm size is strongly dependent on the number of donors doped in a SiNC, i.e., odd or even. Using this model, we also estimate the numbers of P donors included in each SiNC to be 1 to at most 6, which are less than 1/10 of the average P doping concentrations.