Optoelectronic properties simulation of hydrogenated microcrystalline silicon Schottky diode

Microcrystalline silicon has its own macroscopic characteristics which are different from each of the single phase characteristics. Hence, each phase of mu c-Si:H plays an important role in electronic transport. In this paper, we model a basic Schottky structure with a 1 mu m thick, the device considered in our study is an alternance of amorphous and crystalline regions with different fractions (0 to 80%). The latest has a columns shape whose average size between 50 angstrom and 200 angstrom. The heterojunction physics is applied to the region of interfaces between the crystalline and the amorphous components. The numerical solution of the continuity and Poisson's equations by Newton-Raphson method let us to simulate the spectral response and the I(V) characteristic of mu c-Si:H Schottky diode under monochromatic illumination for the wavelength varying between 0.4 mu m and 1.2 mu m and under diverse bias voltage. We observe that the maximum of sensibility of microcrystalline diodes shifts towards higher energies compared with them of amorphous diodes, with normalised efficiency varying from 0.7 to 0.8 and the maximum position varies slightly with crystalline fraction and independently to the applied voltage. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim