ZNTE - A POTENTIAL INTERLAYER TO FORM LOW-RESISTANCE BACK CONTACTS IN CDS/CDTE SOLAR-CELLS

We studied the structural and electronic properties of the ZnTe/CdTe(100) interface with reflection high-energy electron diffraction and angle-resolved synchrotron radiation photoemission spectroscopy (ARPES). ZnTe overlayers grown at 300-degrees-C on CdTe(100) were fully strained and pseudomorphic up to almost-equal-to 16 angstrom. Beyond this coverage the ZnTe film starts to gradually relax the 6.6% in-plane lattice strain. Complete relaxation is reached at a ZnTe coverage of approximately 300 angstrom. A valence-band offset of DELTAE(v) = 0.00+/-0.05 eV was measured with ARPES at the GAMMA point. This propitious band lineup may allow for the use of a ZnTe intermediate layer at metal/CdTe structures to induce ohmic back contacts in CdS/CdTe heterojunction solar cells.