III-V nanostructures beyond nanowires for optoelectronics.

by Hoe Tan (Australian National University)

Tuesday 17 Oct 2023, 16:00 → 17:00 Europe/Rome

Aula Conversi (Dip. di Fisica - Edificio G. Marconi)

Group III-V semiconductors have revolutionised electronics and optoelectronics due to their superior physical and optoelectronic properties including high carrier mobility, direct bandgap and band structure engineering capability. Reducing the device size to nanoscale brings many unique properties, such as large surface-area-to-volume ratio, high aspect ratio, carriers and photons confinement effect. In this talk I will present and discuss our III-V nanostructure research activities at The Australian National University, focusing on (i) shape engineering, (ii) hexagonal boron nitride and (iii) nanofilms.

(i)        Our work on selective area growth of III-V nanostructures shows the possibility of obtaining other functional nanostructures beyond the limitation of rod-like nanowires and opening the way to more advanced device geometries, such as nanomembranes and micro-rings. Our micro-ring lasers have excellent cavity due to the atomically flat facets and operate in the whispering gallery mode. They are important components for integrated photonics applications as light from can these devices can be efficiently coupled to on-chip waveguides.

(iii)     Hexagonal boron nitride (hBN) is a two-dimensional, wide-bandgap semiconductor which is well-known for its thermal and chemical stability, passivation properties and, more recently, as single photon emitters which has applications in quantum computing and cryptography. However, hBN is currently limited to 1-2 mm in size, which is impractical in real applications. I will introduce our work on growing wafer-scale hBN for applications as single photon sources and templates for van der Waals epitaxy.

(iii)     Nanomembrane devices developed at ANU are mere tens of nanometres thick but perform extremely well as optoelectronic devices. These devices can be miniaturised, made into wearable devices, fabricated at low cost, and allow sensitive real-time monitoring of harmful gases (ultrasensitive NO₂ sensors using InP nanomembrane) or UV radiation (photodetectors using GaAs nanomembrane).