Microscopic origin of light-induced ESR centers in undoped hydrogenated amorphous silicon

Article

关键词: ELECTRON-SPIN-RESONANCE;    A-SI-H;    DETECTED MAGNETIC-RESONANCE;    LOCALIZED PARAMAGNETIC STATES;    BAND-TAIL ELECTRONS;    DANGLING-BOND;    DEFECT STATES;    RECOMBINATION;    GERMANIUM;    SEMICONDUCTORS;   

DOI  :  10.1103/PhysRevB.62.15702

来源: SCIE

【 摘 要 】

Si-29 hyperfine (hf) structures of light-induced electron-spin-resonance (LESR) centers of g = 2.004 and 2.01 have been investigated in undoped hydrogenated amorphous silicon (a-Si:H) with different Si-29 content(1.6, 4.7,9.1 at. %) by means of pulsed and multifrequency (3,11,34 GHz) ESR techniques. We have experimentally deconvoluted overlapping LESR signals using the difference in the spin-lattice relaxation time between the two signals. The deconvoluted Si-29 hf structure of g = 2.004 indicates that the wave function of the g = 2.004 center spreads mainly over two Si atoms. Accordingly, we propose that the origin of g = 2.004 is electrons trapped in antibonding states of weak Si-Si bonds rather than those trapped at positively charged dangling bonds. The isotropic hf splittings were estimated to be around 7 mT for g = 2.004 and below 3 mT for g = 2.01, which are in good agreement with characteristics of the antibonding and bonding states of the weak Si-Si bond. We suggest, from our Si-29 hf data and other experimental findings, that the g = 2.004 center is localized spatially more than conduction-band-tail electrons detected by photoluminescence.

【 授权许可】

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