... samples were MLs of alternating layers of a-Si and a-Ge and single layers of a-Si and of a-Ge.The latter ones had a thickness of 40 nm. In the formerstructure, the 2 × 50 alternating layers were ... spectra of H in the a-Si single layers hydrogenated atflow rates of 0.4, 0.8 and 1.5 ml/min (#4, #8 and #15, respectively, in the plot). (b) Total H concentration in a-Si (solid black line) and ... realized from asequence of thin a-Si and a-Ge layers by intermixing them[1,5,6], which is obtained by heat treatments. The lattertreatments are often also used for activating dopants.Previous...