Narrow band gap group III-nitride alloys

Recent results on the properties of narrow gap group III-nitrides and their alloys are reviewed. It is shown that InN with the energy gap of View the MathML source exhibits classical characteristics of a narrow gap semiconductor with strongly nonparabolic conduction band and an energy dependent electron effective mass. With the new discovery, the direct band gaps of the group III-nitride alloys span an extremely wide energy range from near infrared in InN to deep ultraviolet in AlN offering possibilities for new device applications of these materials. We also discuss properties of dilute group III-N–V alloys in which incorporation of a small amount of nitrogen results in a dramatic band gap reduction. All the unusual properties of the alloys are well described by a band anticrossing model that considers an interaction between localized nitrogen states and the extended statOptical properties and carrier recombination dynamics of a series of InN epilayers, with varying free electron concentrations, grown by molecular beam epitaxy were studied by steady-state photoluminescence (PL) and time-resolved differential transmission spectroscopy. At room temperature strong PL around View the MathML source was observed. Temperature-dependent PL measurements show a redshift of the peak energy and a linear increase of the emission linewidth with temperature. Furthermore, our results demonstrate that room temperature carrier lifetimes are inversely proportional to the free electron concentrations for theses samples. Carrier lifetime as long as View the MathML source was observed in the best quality sample, indicating a highly improved crystalline quality.es of the conduction band.