Band Offset Analysis at the Te/ALD-Grown Al 2 O 3 Heterojunction for Transistor Applications

Understanding the interfacial electronic structure between semiconductors and high-k dielectrics is essential for optimizing charge transport, gate control, and device reliability in next-generation electronics. The band alignment of the atomic-layer-deposited aluminum oxide (Al2O3) and p-type tellurium (Te) heterostructure was systematically investigated by using high-resolution X-ray photoelectron spectroscopy. Complementary surface and structural analyses, including X-ray diffraction, Raman spectroscopy, and atomic force microscopy, confirmed the high crystallinity, smooth morphology, and stable chemical bonding of the Te and Al2O3 layers. The experimental results revealed a straddling-gap type-I band alignment with valence- and conduction-band offsets of 3.42 ± 0.05 eV and 2.13 ± 0.05 eV, respectively, indicating favorable interface coupling for p-channel operation. The determined band offsets were consistent with the results predicted by Anderson’s model. Based on the experimentally obtained band parameters, a p-type field-effect transistor incorporating the Te/Al2O3 stack as the channel/gate dielectric interface was designed and analyzed, demonstrating efficient gate modulation and low leakage behavior consistent with the predicted energy band configuration. This study provides fundamental insights into the electronic coupling at the Te/high-k oxide interface and offers valuable design guidelines for reliable, high-performance p-type transistors and complementary logic devices.