An AlAs/germanene heterostructure with outstanding tunability of electronic properties

By means of comprehensive first-principles calculations, we investigate the stability and electronic properties of AlAs/germanene heterostructures. Especially, electric field and strain are used to tailor its electronic band gap. The binding energy and interlayer distance indicate that germanene and AlAs monolayers in AAI pattern are bound together via van der Waals interaction with a maximum indirect-gap of 0.494 eV, which is expected to has potential application in the field of field-effect transistors. Under the negative E-field and compressive strain, the bandgaps of the AAI-stacking show a near-linear and linear decrease behavior respectively, whereas the response of the bandgaps to the positive E-field and tensile strain displays a dramatic and monotonous decrease relationship. All these nontrivial and tunable properties endow AlAs/germanene nanocomposite great potentials for FETs, strain sensors, and photonic devices.