Professor Jo Shien Ng

Departmental Director of Research & Innovation

Staff Photo

Contact Details

Tel: +44 (0)114 22 25173

ORCID ID: 0000-0002-1064-0410


  • PhD (Electronic Engineering), University of Sheffield 2003
  • BEng (Electronic Engineering), University of Sheffield 1999

Research Activity

  • Avalanche photodiodes (APDs)
  • Geiger mode avalanche photodiodes or Single Photon Avalanche Diodes (SPADs)
  • High-performance photodetectors for mid-infrared light detection


  • Professor of Semiconductor Devices
  • Departmental Director of Research & Innovation
  • Teaching: EEE6232 (Physics of Medical Imaging with Ionising Radiation)
  • EEE Women Adviser
  • EEE Athena SWAN team member

I received my B.Eng. degree and Ph.D. degrees in electronic engineering from the University of Sheffield, in 1999 and 2003, respectively. After a postdoctoral position within the EPSRC National Centre for III–V Technologies (now part of EPSRC National Epitaxy Facility) for material and device characterization, I became a Royal Society Research Fellow from 2006 to 2016. I am currently Professor of Semiconductor Devices.

My research is focused on developing a type of light sensors capable of measuring the weakest possible light signals.

There is a wide range of applications that rely on detection of the weakest possible light signal. An example is quantum cryptography (whose encryption key is made up of these very weak light), which currently offers the ultimate encryption safety.

Other key applications for highly sensitive light sensors are high-speed optical communication systems, laser-based ranging (autonomous vehicles and high-resolution geographical mapping), medical imaging (X-ray computed tomography), and non-contact temperature measurements. These systems depend on detecting light so weak that each signal comprises only hundreds or photons (which make up the light) or even down to a single photon.

I am particularly interested in using avalanche photodiodes (APDs) to detect the very weak light. This semiconductor device senses light and gives electrical current that varies with the light intensity. A process called avalanche gain (similar to how snow avalanche grows in size as it accelerates down a snow-covered mountain) in the APDs amplifies the electrical current, improving the system’s performance in terms of signal-to-noise ratios.

My current research themes include Si SPADs for detecting visible light from Raman spectroscopy; low-noise APDs for high-speed optical communication systems; measurements of avalanche gain and noise from novel materials; simulation models for APDs and single photon avalanche diodes (SPADs).

Research Projects

Research income since Oct 2006 is £3.9 million, made up of Principal Investigator (£1.6 million) and Co-investigator (£ 2.3 million approportioned).

Dates Sponsor Grant Title PI/co-I
Jul 15 - Apr 16 Commercial AlInP detectors PI
Jul 15 - Jun 16 Commercial Avalanche photodiodes Co-I
Jul 15 - Jun 18 STFC Linear geiger mode detector technology for time resolved spectral measurements PI
Mar 15 - Feb 17 Royal Society High-performance photodetectors for mid-infrared light detection PI
Jan 15 - Jun 18 EU H2020 PROMIS (Postgraduate Research on Dilute Metamorphic Nanostructures and Metamaterials in Semiconductor Photonics) Co-I
Jan 15 - Jun 15 European Space Agency InAs APD development for NIR & SWIR applications (Extension) PI
Apr 13 - Oct 16 EPSRC Next generation avalanche photodiodes Co-I
Apr 13 - Mar 16 Royal Society Royal Society University Research Fellowship PI
Sept 12 - Aug 15 EPSRC InAsNSb dilute nitride materials for mid-infrared devices & applications Co-I
Jun 14 - Oct 14 Commercial InGaAs/InAlAs APDs PI
Jan 13 - Dec 14 European Space Agency InAs APD development for NIR & SWIR applications Co-I
Dec 12 - Jun 13 Commercial InGaAs/InAlAs APDs PI
Apr 12 - Sept 12 MoD CDE Narrow band APDs for underwater communications Co-I
Mar 11 - Feb 13 EPSRC High performance X-ray detectors with sub-100eV energy resolution PI
Oct 10 - Sept 13 EPSRC Novel InAs avalanche photodiodes for photon counting applications Co-I
Dec 09 - Nov 12 STFC (PIPSS) Knowledge exchange in AlGaAs X-ray detectors PI
Apr 09 - Apr 10 EMRS DTC Detector for Infrared Algorithmic Spectrometer Co-I
Oct 08 - Sept 11 TSB Extended Temperature OptoElectronics II (ETOE II) Co-I
May 08 - Jul 11 EU FP7 Materials for avalanche receiver for ultimate sensitivity (MARISE) PI
May 08 - Jul 10 EPSRC New high-performance avalanche photodiodes based on the unique properties of dilute nitrides Co-I
Nov 07 - Oct 08 MoD CoI Detectors for UV non line-of-sight communication Co-I
Nov 07 - Oct 08 MoD CoI 2 Band Quantum Dot Infrared Photodiodes for Mid- and Long-Wave Infrared Scene Sensing Co-I
Oct 07 - Sept 09 DSTL & STFC Avalanche photodiode array detector for eye-safe 3D imaging PI
Apr 07 - Mar 10 EMRS DTC Infrared photodiodes based on Type-II Superlattices Co-I
Oct 06 - Mar 13 Royal Society Royal Society University Research Fellowship PI
May 06 - Sept 09 European Space Agency Near infrared detectors for LIDAR Co-I
Apr 06 - Mar 09 EMRS DTC Co-I
Oct 05 - Dec 05 EMRS DTC Novel low voltage InAs avalanche photodiodes for affordable 2D IR detectors Co-I
Apr 04 - Sept 06 EU FP6 Secure Communications based on Quantum Cryptography Co-I
Apr 03 - Mar 05 EMRS DTC High sensitivity avalanche photodiodes for imaging and rangefinding Co-I
Research Students

Student Degree Status Primary/Secondary
Goldberg GR MPhil Graduated Primary
Meng X PhD Graduated Primary
Mohmad ARB PhD Graduated Primary
Ong DSG PhD Graduated Primary
Ong S-L PhD Graduated Primary
Dimler SJ PhD Graduated Secondary
Guerrero Moreno MA MPhil Graduated Secondary