Abstract
The temperature dependence of the band gap of GaNxSb1−x films with has been studied in the 1.1–3.3 m (0.35–1.1 eV) range using infrared absorption spectroscopy between 4.2 and 300 K. As with other dilute nitride semiconductors, the temperature dependence of the band gap is reduced by alloying with nitrogen when compared to the host binary compound. However, for GaNSb, the smallest variation of the band gap with temperature is observed for samples with the lowest N content for which the band gap is almost totally insensitive to temperature changes. This contrasts with the more widely studied GaNxAs1−x alloys in which the band gap variation with temperature decreases with increasing N content. The temperature-dependent absorption spectra are simulated within the so-called band anticrossing model of the interaction between the extended conduction band states of the GaSb and the localized states associated with the N atoms. The N next-nearest neighbor pair states are found to be responsible for the temperature insensitivity of the band gap of the GaNSb alloys as a result of their proximity to the conduction band edge giving them a more pronounced role than in GaNAs alloys.
Highlights
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III-V semiconductor causes a strong reduction of the band gap energy. This reduction has been already observed in the dilute nitrides GaNAs6, GaInNAs5, GaNP9, GaNSb8 and in InNAs10 and explained by a two level conduction band anticrossing model (BAC) where the interaction between the host conduction band and resonant nitrogen level results in the formation of two nonparabolic subbands11,12
Summary
To cite this article before publication: Wojciech M Linhart et al 2018 J. Nitrogen pair-induced temperature insensitivity of the band gap of GaNSb alloys pt. The temperature dependence of the fundamental band gap energy of semiconductors represents a basic materialspecific property which is of considerable practical and theoretical interest. It has been shown that the incorporation of a few percentage of nitrogen in Ga(In)As reduces the temperature-induced shift of the band gap energy by 12% in GaInNAs5 and 40% in GaNAs6 compared to GaAs. The effect has been ascribed to the interaction of temperature-insensitive localized N states with extended band states that have a temperature dependence close to that of GaAs6,7. For GaNAs, the temperature dependence of the band gap decreases as the N content is increased, suggesting the possibility of increased
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