Abstract
The present issue of physica status solidi (a) contains recent advances in the physics, chemistry and applications of indium nitride. Its goal is to highlight new developments, and to assess the current re‐search status on this important material as well as novel applications that now appear possible. The pa‐pers were submitted to the last European Materials Research Society (E‐MRS) Fall Meeting, held in War‐saw on 5–8 September 2005.
The symposium dealt with the current controversial issues of the bandgap of InN and the composi‐tion fluctuation in InGaN heterostructures. A reasonable agreement seems to be coming up concerning the bandgap. When In nanocrystals can be avoided, the bandgap is converging to the lowest values below 1 eV. However, local measurements like valence electron energy loss spectroscopy still point out a band gap of 1.7 eV. For the InGaN quantum layers, indium composition fluctuation may be present, and the growth conditions could play a critical role.
The quality of the material has dramatically improved since 2000, the MBE grown InN layers have reached residual carrier concentrations in the low 10^17^ cm^–3^, and good quality heterostructures are now fabricated (InN/InGaN) by molecular beam epitaxy (MBE).
It was a particular concern of the organisers that the symposium should be in the form of a work‐shop so that enough time is allowed for the discussion of the controversial issues. We hoped that this format would promote a healthy and vigorous exchange of ideas. The lively debate in many of the ses‐sions, and the fact that the final session on Thursday evening was the best attended, suggests that we were at least partly successful in this.
The symposium contained over 60 contributions, both metal organic vapour phase epitaxy and MBE techniques of InN were covered, and special attention was given to the optical and structural quality of the thin films. Thirty invited speakers provided the current status of the research on this exciting mate‐rial. In addition to invited papers, fifteen oral presentations contributed to the eleven sessions ranging from heterostructures growth to band gap issues and devices. Moreover, a poster session, which pre‐sented some twenty interesting reports, provided a further forum for detailed discussions. From those papers that were submitted for publication, 26 were judged, each by two referees, to be highly rated and worthy of publication in physica status solidi (a).
This issue is organised in three sections corresponding to the topical sessions of the Symposium. The first deals with band gap issues, optical and electrical properties, the second with the growth of the InN thin films, whilst the last section is concerned with the structural properties of the layers and de‐vices.