Energy-band parameters of atomic-layer-deposition Al2O3∕InGaAs heterostructure

Abstract

The valence-band offset has been determined to be $3.83\pm 0.05\mathrm{eV}$ at the atomic-layer-deposition ${\mathrm{Al}}_2{\mathrm{O}}_3∕\mathrm{In}\mathrm{Ga}\mathrm{As}$ interface by x-ray photoelectron spectroscopy. The $\mathrm{Au}–{\mathrm{Al}}_2{\mathrm{O}}_3∕\mathrm{In}\mathrm{Ga}\mathrm{As}$ metal-oxide-semiconductor diode exhibits current-voltage characteristics dominated by Fowler-Nordheim tunneling. From the current-voltage data at forward and reverse biases, a conduction-band offset of $1.6\pm 0.1\mathrm{eV}$ at the ${\mathrm{Al}}_2{\mathrm{O}}_3–\mathrm{In}\mathrm{Ga}\mathrm{As}$ interface and an electron effective mass $\sim 0.28\pm 0.04m_0$ of the ${\mathrm{Al}}_2{\mathrm{O}}_3$ layer have been extracted. Consequently, combining the valence-band offset, the conduction-band offset, and the energy-band gap of the InGaAs, the energy-band gap of the atomic-layer-deposited ${\mathrm{Al}}_2{\mathrm{O}}_3$ is $6.65\pm 0.11\mathrm{eV}$ .