The pulsed PECVD involves modulation of standard 13.56 MHz RF plasma in the kHz range. This allows an increase in the electron density during the 'ON' cycle, while in the 'OFF' cycle neutralizing the ions responsible for dust formation in the plasma. In this work, we report the development of state of the art nano-crystalline Si (nc-Si:H) materials using Pulsed PECVD technique with 220 crystallite orientation, grain size of ~200 Å, low O concentration and a minority carrier diffusion length, L d , of ~1.2 µm. The crucial effects of p/i interface and the incubation layer have been investigated and an efficiency of ~7.5% for single junction nc-Si:H p-in device has been achieved for the i-layer thickness of 1.4 µm, using non optimized textured substrates.

Use of a pulsed plasma-enhanced-chemical-vapor-deposition technique for "state of the art" a-Si:H materials and solar cells at a deposition rate of up to 15 Å /sec using a modulation frequency in the range of 1 -100 kHz is reported. The approach has also been developed to deposit materials and devices onto large-area, 30 cm £ 40 cm, substrates with thickness uniformity of , 5%, and a large gas utilization rate of . 25%.In a newly developed "Hot Wire" chemical vapor deposition method, a graphite filament material, has so far shown no appreciable degradation after deposition of 500 mm of amorphous silicon. It is reported that this technique can produce "state-of-the-art" a-Si:H and that a solar cell of p/i/n configuration exhibited an initial efficiency approaching 9%.The use of microcrystalline silicon (mc-Si) materials to produce low cost stable solar cells is gaining considerable attention. It is demonstrated that both of these techniques can produce thin film mc-Si, dependent on process conditions, with 111 and/or 220 orientations and with a grain size of approximately 500 Å . Inclusion of these types of materials into a solar cell configuration is discussed.

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The Pulsed PECVD technique involves modulating the standard 13.56 MHz RF plasma, in the kHz range. This allows an increase in the electron density during the ‘ON’ cycle, while in the ‘OFF’ cycle neutralizing the ions responsible for dust formation in the plasma. In this work, we report the increase of i-layer growth rate and silane gas utilization rate (GUR) for amorphous Si p-i-n solar cells grown in a large area (30 cm × 40 cm) single chamber deposition system. The i-layer growth rate of 5.4 Å/sec with a GUR of >15% has been achieved, which shows a device efficiency of 8.3% (almost same as of our conventional PECVD grown a-Si:H solar cell with ilayer growth rate of ∼1 Å/sec). We also deposited microcrystalline Si p-i-n devices using the Pulsed PECVD technique. The crystallite orientation of the films changes from a random to a (220) orientation near the microcrystalline-to-amorphous transition. The effects of crystallite orientation, grain boundaries and ion bombardment during growth on the solar cell performances are investigated. An efficiency of 4.8% for single junction μc-Si:H p-i-n device has been achieved for the i-layer thickness of 0.9 μm.