Optimizing photocurrent intensity in layered SiGe heterostructures

Abstract

Abstract We study the dependence of photo-spectral intensity on tri- and multilayers of SiO2/[SiGe [ d SiGe ]/SiO2] N with repetitions N = 1 to 10 and thicknesses d SiGe = 5 –100 nm. Photocurrent analysis reveals a bimodal spectral feature. A comparison of the photocurrent analysis between tri- and multilayers shows that in the multilayer structures, the photo-spectral intensity increases with increasing repetition N. The change in intensity could then be further tuned by changing the thickness of the SiGe layers d SiGe . We attribute the change in intensity to an increase in tensile strain, along with increased Ge atomic concentration and reduced SiGe-nano cluster size.