Similarities in the Valence Bands of Amorphous and Crystalline GeTe Determined by X-Ray Photoemission

We have measured the valence-band density of states and the energies of the core levels of crystalline and amorphous GeTe with x-ray photoemission. The density of states of the amorphous form is found to be very similar to that of the crystal. The present results indicate that the atomic orbitals primarily determine the valence-band density of states and that these are disturbed little, even when the bonding changes significantly.