Pulsed EPR and ENDOR Study of SiC Nanopowders

D. Savchenko Institute of Physics, AS CR, Na Slovance 2, 18221, Prague 8, Czech Republic and V.E. Lashkaryov Institute of Semiconductor Physics, NASU, 03028, Kiev, Ukraine

Full Text PDF

In this work field-sweep electron spin echo and pulsed electron nuclear double resonance study of the silicon carbide (SiC) nanoparticles (np-SiC) of different sizes is presented. Nitrogen (N) triplet lines due to the isolated N donor state was observed in np-SiC with grain size d>100 nm. With a decrease of the particle size up to 50 nm the N triplet lines transforms into one single exchange line due to the delocalization of the donor wave function caused by the size confinement effect. Along with N donors the carbon vacancy (VC) located in cubic phase was observed in np-SiC with d<100 nm. The further decrease of the grain size to d<50 nm leads to the appearance of the VC located in hexagonal crystalline phase and carbon dangling bonds located in the carbon excess phase of np-SiC. The fact that only N donor center at "k2" quasi-cubic position substituting Si site was observed in the field-sweep electron spin echo and pulsed electron nuclear double resonance spectra of np-SiC was explained by high compensation degree of the samples and the presence of carbon excess in np-SiC. The appearance of the proton electron nuclear double resonance signal in no-SiC with d<100 nm indicates that the hydrogen retention in np-SiC increases with decreasing of grain size.

DOI: 10.12693/APhysPolA.126.1063 PACS numbers: 76.30.-v, 76.70.Dx, 81.07.Wx