Kentaro Sawano

Effects of spacer thickness on quantum efficiency of the solar cells with embedded Ge islands in the intrinsic layer

We report on the effects of spacer thickness on the external quantum efficiency (EQE) of the solar cells with Ge islands embedded into the intrinsic region of the Si-based p-i-n diode. The EQE response of the solar cells in the near-infrared region is dependent on the spacer thickness that separates the layers of self-assembled Ge islands. It was found that the EQE response has an optimum value when the spacer thickness can sustain a good vertical ordering of islands. On the other hand, random nucleation of islands due to a thicker spacer layer exhibits an inferior EQE response. Furthermore, a drastic decrease of the EQE response of the solar cells for a thinner spacer layer was observed.

Detection of Effect of Uniaxial Strain on the Valence Band of SiGe by HXPES with High Spatial Resolution

We have observed for the first time a change in the binding energy of valence band top, Si 1s and Ge 2p core level by the uniaxial strain and biaxial strain.