Abstract
The present disclosure coats an amorphous silicon (Si) layer on a doped Si substrate of a solar cell. Or, a silicon dioxide (SiO2) layer is grown on the doped Si substrate and beneath the amorphous Si layer. A heterojunction interface and a homojunction interface are formed in the solar cell in a one-time diffusion. Thus, a heterojunction solar cell can be easily fabricated and utilities compatible to those used in modern production can still be used for reducing cost.