A p-Ge C /n-Si Heterojunction Diode Grown by Molecular Beam Epitaxy

We report on the fabrication and characterization of the first p-n diode made from a heterojunction of epitaxial p-type Ge0:998C0:002 on an n-type Si substrate. Epitaxial Ge0:998C0:002 was grown on a (100) Si substrate by solid source molecular beam epitaxy. The p-GeC/n-Si junction exhibits diode rectification. The I-V characteristics of the p-GeC/n-Si diode indicate a reasonable reverse saturation current of 89 pA/ m2 at 1 V and a high reverse breakdown voltage in excess of 40 V. Photoresponse from the Ge0:998C0:002 p-n diode was observed from 1.3m laser excitation resulting in an external quantum efficiency of 1.4%.