Resonant photothermal bending spectroscopy (RPBS) at various measurement temperatures has been developed for estimating absorption coefficient (α) spectra of thin film semiconductors. The experimentally obtained sensitivity of RPBS was about ten times larger than nonresonant PBS. In vacuum, this technique has been applied to estimate the α spectrum of hydrogenated microcrystalline silicon (μc-Si:H) films at the measurement temperatures from 25 to 150 °C. It is demonstrated that the temperature coefficient of an indirect optical absorption at 1.2–1.8 eV caused by Si microcrystallite is almost the same as that of single crystalline silicon, and the temperature coefficient of below-gap absorption intensity is negative. The reason for the negative temperature coefficient and the energy level of the localized state resulting in the below gap absorption are discussed.

A real time ellipsometry study of the growth of amorphous silicon on transparent conducting oxides Effect of the surface condition on the conductance of hydrogenated amorphous silicon

A systematic deposition of hydrogenated amorphous silicon films from pure SiH4 plasma was made in a capacitively coupled rf glow-discharge system by changing anode–cathode spacing d and chamber pressure p simultaneously. The data of the deposition rate in the p-vs-d space had two boundaries. One was pd=const. The other seems to be pd2=const. The rf plasma can stably sustain between the boundaries. The boundaries are discussed with rf power per SiH4 molecule and with overlapping Paschen’s lines of various fragments, especially H2 due to the SiH4 dissociation. We found the optimum conditions in which the deposition rate was more than 10 Å/s without large photo-induced degradation. 10% efficient p-i-n solar cells were achieved with the intrinsic layer deposition rate of 3.9 Å/s and more than 6% efficiency with 10 Å/s.

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