A critical role of p/i interface in nanocrystalline single junction p-i-n solar cells

The role of p/i interface in nanocrystalline Si p-i-n type solar cells is very critical due to the fact that the nc-Si grown by CVD technique often starts with an amorphous incubation phase, the extent of which sensitively varies with the film growth conditions. We used the reflectance spectra at UV region, where the additional reflections (at 365 nm and 275 nm) appear due to the presence of any crystalline phase, to get an idea about the structure of the film at p/i interface. In this work, the usual pulsed PECVD technique has been modified to provide for extra degrees of freedom to manipulate the growth surface reactions and hence the control of initial film growth via altering the density and energy of various radicals (like H, SiH/sub 3/ etc.) and ions. The use of modified pulsed PECVD method for a surface treatment on nc-p layer leads to an elimination or a reduction of the incubation layer at the p/i interface and thereby improves the device performances significantly.