Sheffield Bismide Semiconductors Research Group


Welcome to the website of the University of Sheffield dilute bismides research group! The main objectives of the group are the growth and characterisation of III-V-Bi compound semiconductors, such as GaAsBi, InAsBi, and InGaAsBi. All of our growth prior to Summer 2016 was performed using an Omicron solid source MBE-STM system, with 11.8x11.4 mm square samples. As of Summer 2016 we also have a VG V80 MBE system, which was kindly donated by Imperial College London.

Our main experimental facilities are located in the University of Sheffield Nanoscience and Technology Centre, in the same building as the EPSRC National Epitaxy Facility. We also have access to the advanced detector centre in the Portobello building, which is used for a wide variety of opto-electronic measurements.

The replacement of a small fraction of the group V atoms in the host material with bismuth causes a dramatic decrease in the band gap, leading to a wide range of potential applications. These include photovoltaics, infra-red photodiodes, spintronics, and several different laser applications. At Sheffield we are particularly interested in the integration of GaAsBi into multi-junction solar cells and photo-detectors. We also have a strong interest in researching the growth and fabrication techniques that are necessary to achieve high device performance.


Contact Prof. John David or Dr. Robert Richards for information on positions in the group.

Useful Links

Advanced Detector Centre

Epitaxy Explained

Semiconductor Materials and Devices Group

Figure left:

Electroluminescence of GaAsBi pin diode with varying injection currents (1, 2, 5, 10 mA), as viewed with the probing camera. The EL has a peak around 930 nm. The camera is supposed to have an infra-red blocking filter, which is clearly not very effective!

Contact Details

Email addresses for all members of our group are available on the personnel page.


Room 204, Lab 104

Nanoscience and Technology Centre

University of Sheffield

Broad Lane

S3 7HQ

Recent News and Events

December 2017

  • Paper published by our group, in collaboration with Imperial College London! The paper, titled "Photovoltaic characterisation of GaAsBi/GaAs multiple quantum well devices", has been published in the Solar Energy Materials and Solar Cells journal

October 2017

  • New paper published in Scientific Reports by our collaborators in Wroclaw! The title of the paper is "Deep-level defects in n-type GaAsBi alloys grown by molecular beam epitaxy at low temperature and their influence on optical properties".

September 2017

  • Welcome to Nick Bailey and Mohamad Riduwan Md Nawawi, who have joined our research group!

August 2017

  • Another power cut to the University.

July 2017

  • Robert Richards attends 8th International Conference on Bismuth Containing Semiconductors, in Marburg. Contributions from our group include "Hole Trapping in GaAsBi/GaAs MQWS", "Impact Ionization in GaAsBi Diodes", and "Electroluminescence and Current-Voltage Measurements of GaAsBi pin Diodes".

May 2017

  • Robert Richards attends Compound Semiconductor Week 2017 in Berlin

April 2017

  • Our poster titled "Opto-Electronic Measurements of GaAsBi pin Diodes" wins an award for "best poster" at SIOE 2017 in Cardiff!
  • Robert Richards and John David attend SIOE 2017 in Cardiff
  • Robert Richards, Thomas Rockett, and Yuchen Liu attend UK MBE users meeting, organised by Heriot Watt University in Edinburgh
  • Achieve first vacuum in V80 FEL and prep-chamber, 8e-6 mBar! Wobble sticks in prep-chamber were slightly damaged during transit from London. Main gate valve replaced.

March 2017

  • MBE-STM sample heater stage found to be contaminated, machine brought down
  • Beryllium cell shutter clogged with gallium

February 2017

  • MBE-STM machine back up and running
  • New paper accepted for publication in the Journal of Crystal Growth. Paper titled "Influence of Growth Conditions on the Structural and Opto-electronic Quality of GaAsBi" by Thomas Rockett

Our location: Nanoscience and Technology Centre