Comparison of band-gap shrinkage observed in luminescence from n ⁺-Si with that from transport and optical absorption measurements

Abstract

The luminescence data of Schmid, Thewalt, and Dumke on heavily doped n-type Si have been analyzed and compared with the published band-gap shrinkage results of infrared absorption measurements and of transport measurements in bipolar transistors with heavily doped bases. The gap shrinkage observed in luminescence behaves similarly to that observed in transport. The luminescence results are consistent with a density of filled states characteristic of a parabolic conduction band. It is argued that the comparison of the results of luminescence, absorption, and transport measurements indicates a nonrigid gap shift.