Key points are not available for this paper at this time.
A sharp optical absorption edge has been found at about 0. 5 eV for amorphous Ge on a quartz substrate. The edge is comparable in sharpness with the direct edge of crystalline Ge. No evidence for tailing of the band edges into the forbidden band or for a high density of states in the forbidden band is found by these optical measurements. A new density determination gives a value of 4. 54 0. 14 g/cm^3.
Donovan et al. (Mon,) studied this question.