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Research @ Mandela

Research Chair: Nanophotonics

Professor JR Botha

Primary discipline: Physical Sciences

Faculty: Science

Relevance of research

Apart from the very interesting fundamental phenomena manifesting themselves on the nano and quantum scales, and the challenges associated with manipulating and manufacturing semiconductor structures on these scales, this work is aimed at serving a local niche industry involving the manufacture of infrared sensors. The group also aims to develop improved procedures to manufacture new materials and structures for light-emitting and light-detecting devices operating both in the ultraviolet and in the infrared ranges.

Overall, we strive to be at the forefront of international development and offer high-quality training, as evidenced by several collaborations with overseas groups, which provide ample opportunity for students to travel abroad.

Biosketch of incumbent

Professor Botha completed his PhD in Physics at the Nelson Mandela Metropolitan University (formally known as the University of Port Elizabeth) where he holds a Professorship. He is a Von Humboldt Fellow, with extensive experience in the epitaxial growth of semi-conducting layers and heterostructures, including quantum structures, and has expertise in various electrical and optical techniques suitable for characterising nanostructures. He has published almost 100 papers in peer-reviewed international journals.

Current research interests

Professor Botha has numerous challenging projects, including:

  • InAsSb and related nanostructures for application in mid-infrared detectors. This work includes the development of InAs/GaInSb strained layer superlattices and InAsSb quantum dots by MOCVD;
  • The development of ZnO and MgZnO by MOCVD for ultraviolet detectors. This project focuses on issues such as p-type doping in ZnO (one of the outstanding issues preventing this exciting material from yielding high-quality photo diodes), and the prevention of phase separation in MgZnO, in order to produce high-quality ZnO/MgZnO quantum structures;
  • Chemical bath deposition of ZnO nanorods on silicon substrate for white light emitters. This work addresses the challenges of controlling the orientation and dispersion of nano seed crystals on silicon substrate, to act as templates for the formation of ZnO nanorods. It is also aimed at controlling the shape and size of the ZnO nanorods; and
  • MOCVD growth and characterisation of antimony based quantum dot structures for photovoltaic and mid-infrared sensor applications.