Electron spin resonance study of the dangling bond in amorphous Si and porous Si

We compare the electron spin resonance (ESR) signal of the dangling bond in porous silicon (PS) layers, produced by electrochemical etching, to the ESR signal from hydrogenated amorphous Si(a-Si:H) films. The anisotropy of the ESR signal from PS showed g values varying as for the Pb Si/SiO2 interface dangling bond. The g value varies from g∥=2.0020 to g⊥=2.0080 with an inhomogeneously broadened line width increasing from 1.8 to 3.8 G. An ESR powder line, with superhyperfine and strain broadening intrinsic to PS, has more anisotropy in g∥−g⊥ and less inhomogeneous broadening than does the dangling bond line in a-Si:H. No evidence was seen for light-induced metastability on a H-passivated PS film.