TAILORING REFRACTIVE-INDEX OF A-SI-H BY TBP (C4H11P) DOPING

The refractive index, n, and extinction coefficient, k, of n-type TBP (tetriarybutylphosphine) doped a-Si:H films is reported. TBP is prefer red over phosphine because of its lower toxicity and pyrophoricity. Th e films were deposited using glow discharge (plasma lab mu P) techniqu e. The optical constants, n, k and absorption coefficient, a are deter mined as functions of wavelength, lambda and doping concentration. The refractive index is found to decrease as the TBP/SiH4 ratio increases from 0.1% to 3%. This decrease is due to increase in the internal str ain in amorphous network. Also the refractive index and extinction coe fficient decrease with increase in wavelength in the range of 600 to 9 00 nm.