Published online by Cambridge University Press: 01 January 1993
Effective densities of states in conduction and valence band, Nc and Nv, are usually set to a fixed value of 1019 to 1020 cm−3 in all computer simulations of a-Si structures. In this contribution the densities Nc and Nv are analytically expressed for different selected extended states distributions. The derivatives d(lnNc)/dx and d(lnNv)/dx, representing specific terms in transport equations, are expressed as function of position dependent band structure. The effect of an increased disorder in heterojunction is simulated by Gaussian distribution of states in a linearly graded heterojunction region.