Available student project - Visible wavelength nanowire lasers

Research fields

  • Photonics, Lasers and Nonlinear Optics
  • Nanoscience and Nanotechnology
Nanowire lasers

Project details

Nitride-based semiconductors, such as GaN, InGaN and AlGaN, are materials that are used in ubiquitous white, blue and green LEDs, and laser diodes.

Nanowires are quasi-1D structures having diameters of a few tens to hundreds on nm but with lengths of um’s. They act as excellent optical waveguides and confine light along their axis. The ends of the nanowire act as tiny mirrors and form a cavity, eliminating the need for specialised processing steps to form a cavity or coupling to an external cavity. This reduces the foot-print of the devices allowing for high density integration. The shape of the nanowires also allows for easy out-coupling of laser light into optical fibres. Nitride-based semiconductors have bandgaps covering the entire visible wavelength, however the efficiency of the laser drops dramatically in the green region and beyond. In this project we will focus on nanowire lasers operation in the yellow-green wavelength region, which has applications in the biotechnology and medical science areas such as flow cytometry, photocoagulation of blood vessels and phototherapies for skin treatment.

This project can be divided into three main modules in which students may choose any combination of modules or any aspects of each module depending on interests of the students and duration of the program:

-          The first module is to develop an analytical and/or numerical modelling technique to understand the gain and cavity properties of semiconductor nanowires. This will then allow the exact geometry and dimension of the nanowires to be designed to achieve lasing. The introduction of quantum confined structures such as quantum well tubes will also be investigated.

-          The second part is to synthesise the nitride nanowires using our new MOCVD system and understand, through various structural, electrical, and optical characterisation techniques, how to (i) improve the material quality, (ii) efficiently dope this semiconductor, (iii) control the composition and material, and (iv) engineer the bandstructure of multilayer structures.

-          The third part of the project involves (i) the design of the laser structures, (ii) the use of our device fabrication facilities to transform these nanostructures into lasers and (iii) characterising the performance and properties of these lasers to understand the underlying physics of the devices.

Required background

Physics, Material Science, Engineering

Project suitability

This research project can be tailored to suit students of the following type(s)
  • 3rd year special project
  • PhB (1st year)
  • PhB (2nd or 3rd year)
  • Honours project
  • Phd or Masters
  • Vacation scholar

Contact supervisor

Jagadish AC, Chennupati profile
Distinguished Professor

Other supervisor(s)

Mokkapati, Sudha profile
Tan, Hoe profile
Head of Department

Updated:  17 August 2017/ Responsible Officer:  Director, RSPE/ Page Contact:  Physics Webmaster