Surface dangling bonds are a cause of B-type blinking in Si nanoparticles

Abstract

Exponential blinking statistics was reported in oxidized Si nanoparticles and the switching mechanism was attributed to the activation and deactivation of unidentified nonradiative recombination centers. Using ab initio calculations we predicted that Si dangling bonds at the surface of oxidized nanoparticles introduce defect states which, depending on their charge and local stress conditions, may give rise to ON and OFF states responsible for exponential blinking statistics. Our results are based on first principles calculations of charge transition levels, single particle energies, and radiative and nonradiative lifetimes of dangling bond defects at the surface of oxidized silicon nanoparticles under stress.

Carrier recombination mechanism at defects in wide band gap two-dimensional materials from first principles

“…Physically, the phonon-assisted non-radiative rate is dominated by a charge transfer process between initial and final state potential energy surfaces, and can be approximated by a classical Marcus' theory picture (see Figure 1). Given the form of the energy barrier for charge transfer 29 , a large energy difference between the two states (ZPL) results in an exponential drop in the transfer rate (although exceptions can be found 28,[59][60][61] ). Therefore, in monolayer h-BN, the large ZPLs of defect-band transitions result in extremely slow non-radiative recombination processes (over milliseconds).…”

Dynamics of recombination via conical intersection in a semiconductor nanocrystal

“…Among them, silicon dangling bond defects have been studied extensively. 34 – 38 In general, there are two common types of dangling bond defects: P b centers, which are dangling bonds on a three-coordinated silicon atom on the surface, and D centers, which are DB defects located in amorphous silicon. 39 DB defects have been known to degrade the performance of silicon-based devices for both photovoltaic 40 , 41 and light emission 38 , 42 – 44 applications.…”

Sizing Up Excitons in Core–Shell Quantum Dots via Shell-Dependent Photoluminescence Blinking

“…At sub-Bohr dimensions, mobile charge-carriers will frequently sample the QD-surface and core, as well as the host-medium surrounding the QD. As such, interfacial-states arising from unterminated bonds 9,10 and the QDhost dielectric mismatch, 11,12 along with trap-states on ligands 13,14 and in the host, 15,16 will all influence charge-carrier transport and recombination at the nanoscale. At the single-QD level, exciton-dynamics manifest as intermittency or blinking between radiative, on-states and quenched, off-states in the temporal evolution of the PL intensity trajectory.…”