Berlin 2018 – scientific programme

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O: Fachverband Oberflächenphysik

O 113: 2D materials beyond graphene: TMDCs, silicene and relatives V

O 113.8: Talk

Friday, March 16, 2018, 12:15–12:30, MA 043

Lateral and Vertical Heterostructures of h-GaN/h-AlN: Electron Confinement, Band Lineup, and Quantum Structures — •Engin Durgun, Abdullatif Onen, Deniz Kecik, and Salim Ciraci — Bilkent University - UNAM, Bilkent Ankara Turkey

Lateral and vertical heterostructures constructed of 2D h-GaN and h-AlN display novel electronic and optical properties and diverse quantum structures to be utilized in 2D device applications. Lateral heterostructures formed by periodically repeating narrow h-GaN and h-AlN stripes, which are joined commensurately, behave as composite semiconducting materials. Direct-indirect characters of the band gaps and their values vary with the widths of these stripes. However, for relatively wider stripes, electronic states are confined in different stripes and make a semiconductor-semiconductor junction with normal band alignment. This way 1D multiple quantum well structures can be generated with electrons and holes confined to h-GaN stripes. Vertical heterostructures formed by thin stacks of h-GaN and h-AlN are composite semiconductors with a tunable fundamental band gap. However, depending on the stacking sequence and number of constituent sheets in the stacks, the vertical heterostructure can transform into a junction, which displays staggered band alignment with electrons and holes separated in different stacks. Despite the complexities due to confinement effects, the band diagram of the heterostructures and band lineup are conveniently revealed from the electronic structure projected to the atoms or layers. Prominent features in the optical spectra of the lateral composite structures are observed.