In general, it is desirable for the band gap of a tunnel barrier to straddle the gap of the semiconductor in order to provide a barrier for both electrons and holes. However, in the case of InAs, because the Fermi level is pinned in the conduction band at the surface, only electron transport is relevant and hence a tunnel barrier for electrons is needed. ZnTe and CdSe have wide band gaps of 2.26 eV and 1.75 eV, respectively. The cubic(Zinc Blende) phases of InAs, ZnTe, and CdSe have similar lattice parameters with lattice mismatches of approximately 0.5% for InAs/ZnTe, 0.3% for InAs/CdSe, and 0.2% for ZnTe/CdSe. Based on their bulk band edge positions, the band gaps of both ZnTe and CdSe are expected to straddle the gap of InAs. Epitaxial growth of ZnTe and CdSe on InAs{100} and on each other, has been investigated in the context of visible wavelength semiconductor electronics, mid-IR lasers, spin-related phenomena, 49-51 and as barriers in InAs-based heterostructures. Studies of the ZnTe/Al and CdSe/Al interfaces have aimed to elucidate the physics of metal-semiconductor interfaces in the context of devices such as light emitting diodes (LEDs) and Schottky diodes, where the Fermi level position and interface structure are of importance. Therefore, it should be feasible to grow epitaxial InAs/Al interfaces with ZnTe or CdSe as a tunnel barrier.