Electronic Structure of Band-Tail Electrons in a Si:H

Electronic structures of the light-induced electron spin resonance (LESR) centers in undoped a-Si:H have been investigated by means of pulsed ESR techniques. Overlapping LESR signals of g = 2.004 and 2.01 have been experimentally deconvoluted by using the difference in spin-lattice relaxation time between the two signals. The 29Si hyperfine structures of the 2.004 signal clearly show that the wave function of this center spreads mainly over two Si atoms, which suggests that the origin of g = 2.004 is electrons trapped at antibonding states of weak Si-Si bonds