Radiation-induced paramagnetism ina-Si:H

Abstract

Several paramagnetic centers have been observed in doped and undoped $a$-Si:H after x irradiation at 77 K. The paramagnetic responses in nominally undoped $a$-Si:H include (1) an increase in the Si "dangling-bond" line, and (2) trapped N${\mathrm{O}}_2$ molecules. In O- and N-doped hydrogenated $a$-Si [$a$-Si:(H,O,N)] at least four responses are observed: (1) an increase in the Si "dangling-bond" line, (2) an oxygen-associated hole center which is probably a singly coordinated oxygen bonded either to a silicon or to another oxygen, (3) an $s{p}^3$-hybridized dangling bond on a silicon which is bonded to three oxygens ($E^{\prime }$ center), and (4) neutral, atomic hydrogen trapped in the $a$-Si:(H,O,N) matrix.