FEIT Research Project Database

Future low-loss photonic devices at telecomm wavelengths

Project Leader: M Usman
Primary Contact: M Usman (muhammad.usman@unimelb.edu.au)
Disciplines: Electrical & Electronic Engineering

Target applications: Photonic devices, Photovoltaics, Spintronics

Designing new materials with engineered band-structure properties is a topic of intense research interest in materials science and electrical engnieering communities. While traditionally Arsenides, Phosphides, and Nitrides have been the focus of research for photonic and optoelectronic devices, recently a new class of materials known as Bismides have emerged as promising medium for the design of nanophotonic devices working in the mid to far infrared range of wavelengths. Bismides, which are typically formed by replacing a small fraction of As atoms in GaAs or InAs with Bi atoms, offer unique properties at the band-structure level which can be exploited to overcome a number of challenges present in today’s devices. For example, Auger loss mechanism that severely degrades the efficiency of today’s InP-based devices is expected to be suppressed in Bismide based devices due to crossover between band gap and spin split-off energies. A large tuning of the band gap energy as a function of Bi fraction of alloy offer opportunities for targeting wavelengths in telecommunication and infrared range. Other potential applications for Bismide alloys are in the field of photovoltaics and thermoelectric devices.

We have developed a comprehensive atomistic tight-binding framework to investigate the electronic and optical properties of Bismide alloys and quantum well. Our results have shown that by increasing Bi fraction above 10-11%, band gap energy reduces below spin split-off energy, a proof-of-concept for Auger-loss free photonic devices. Atomistic resolution studies have predicted a crucial role of alloy disorder related effects, with important implications towards understanding device characteristics and designing future devices with tailored functionalities.

In this project, students will investigate electronic and photonic properties of bismide nanostructures and develop new devices with optimised functionalities.

Selected references

M. Usman, Nanoscale, 11, 20133, (2019)

M. Usman et al., Phys. Rev. Applied 10, 044024, (2018)

M. Usman, Phys. Rev. Materials 2, 044602, (2018)

M. Usman et al, APL 104, 071103, (2014)

M. Usman et al, PRB 87, 115104, (2013)

M. Usman et al, PRB 84, 245202, (2011)