InN and InGaN crystal growth and structural and property characterization

Abstract

Since it has the narrowest band gap among group III nitride semiconductors, InN has been expected to be a promising material for future optical and electronic devices. InN, however, has been the least studied because of the difficulty of InN crystal growth. The fundamental band gap of InN has long been considered to be approximately 1.9 eV. After it has become possible to grow high−quality InN very recently with developments of epitaxial growth technology, many experimental results have been presented, suggesting that the true band−gap energy of InN should be 0.7〜0.8 eV. In this paper, the recent developments of RF−MBE growth technology of InN and InGaN are reviewed. The true band−gap energy of InN is discussed on the basis of results of crystallographic, optical and electronic characterizations.