Professor Peter M Smowton
Head of School, Physics and Astronomy
Managing Director of the Institute of Compound Semiconductors
Condensed Matter and Photonics Group
I am interested in the physics of semiconductor materials and devices and particularly in those properties relevant for the integration of different materials and different functions. I am currently Director of the EPSRC Future Compound Semiconductor Manufacturing Hub, which focuses on the manufacturing processes for the materials and devices that drive much of the technology that underpins our lives. I am Managing Director of the Institute of Compound Semiconductors, which is a University translational research facility focussed on the fabrication of Compound Semiconductor devices and integrated systems. I collaborate extensively within Cardiff University, with other leading universities worldwide and with UK based industry to develop solutions for the next generations of semiconductor based technology that underpins our connected world.
I supervise 3rd and 4th year projects.
Other recent modules include:
PX3243 "Laser Physics and Non-linear Optics"
PX3144 "Electromagnetic Radiation Detection".
PX2107 "Electronics and Instrumentation" PX2108 "Topics in Physics"
PX3226 "Physics of Semiconductor Devices"
PX1217 "Investigative Physics II" and
PX0202 "Electricity, Magnetism and Light
Interests include the design, fabrication and characterisation of optoelectronic devices. Current research topics include quantum dot lasers , high power emitters for photodynamic therapy and the physics of InGaN light emitting devices. I am also interested in optoelectronic integration of materials and functions. This involves the exploration of the physics of the light matter interactions in these materials and devices.
I am interested in supervising PhD students in the general areas of:
- Compound Semiconductor Device Physics
- Manufacturing Compound Semiconductor Devices
- Integrated Photonics
- III-V semiconductor based microfluidics
I have supervised 29 successful PhD candidates to date. The most recent was:
Dr Sara-Jayne Gillgrass
This thesis describes the work carried out to provide a proof of principle coupled-cavity laser
measurement for blood cell analysis, using an integrated device with capillary fill microfluidics.
The development of both light source and microfluidics on the same sensing platform provides
complete integration and removes the dependence on external systems.
In principle, InAsP quantum dot lasers, cover a wavelength range extending into the near infrared,
where the response of biological matter can provide useful diagnostic information. The suitability
and limitations, of both an InAsP quantum dot and GaInP quantum well active medium, are considered
for the coupled-cavity structure. A InAsP quantum dot structure with an 8 nm AlGaInP
barrier between each dot layer was seen to have a slight improvement in device performance, but
optical gain measurements indicated that this structure would not provide sufficient gain to overcome
the high losses expected in the integrated device. Consequently, a GaInP quantum well was
considered a sensible choice for a proof of principle coupled-cavity measurement.
The efficiency of an etched facet is key to overall performance in the coupled-cavity device and
has been quantified using the gain characteristics of the quantum well structure. A value of facet
efficiency was found to be hf = 0.37 0.04, which is valid for all angles of etched facet. A very
low facet reflectivity of 4.9x109 was measured for a laser with a 14.1o etched facet.
Perturbation of the optical coupling between two laser/detector sections causes a change in the
measured photo-voltage signal from the device. This effect has been employed to demonstrate
detection of both 10 and 6 mm microbeads. In a coupled-cavity regime, a 22.6o angled facet
coupled-cavity laser pair has been shown to have a lower threshold current density than either of
its individual sections, indicating its potential for sensing applications.