Unusual luminescence lines in GaN

Abstract

Optical properties of GaN epilayers and GaN/AlGaN quantum wells grown by molecular beam epitaxy on GaN(0001) single crystal substrate A series of sharp intense peaks was observed in the low-temperature photoluminescence spectrum of unintentionally doped GaN in the photon energy range between 3.0 and 3.46 eV. We attributed the majority of these peaks to excitons bound to unidentified structural and surface defects. Most of the structural-and surface-related peaks ͑at 3.21, 3.32, 3.34, 3.35, 3.38, and 3.42 eV͒ were observed in Ga polar films. In N polar GaN, we often observed the 3.45 eV peak attributed to excitons bound to the inversion domain interfaces.

Surface changes by GaN photoelectrochemical treatment using various electrolytes with and without C2H5OH

“…This imperfectness may be affected by oxygen existence because not only nitrogen but also oxygen was observed by EDS. These results are also supported that the Yi lines relate to structural and surface defects or unidentified point defects segregating threading-edge dislocation [10,11].…”

Time-resolved spectroscopy on GaN nanocolumns grown by plasma assisted molecular beam epitaxy on Si substrates

“…17,19,21,24,25 Contrary to Ref. 23, we discard the possibility that this line corresponds to the so-called Y 1 transition assigned to inversion domains in N-face GaN, 26 although it is well known that MBE growth may result in N-face GaN. As a matter of fact, recent studies by convergent beam electron diffraction have established that GaN NCs, grown by us or other groups by MBE, do grow with Ga polarity.…”

“…6͔, unlike what is reported for the Y 1 line. 26 Therefore, we assign the 3448.5 meV luminescence to the TES.…”

Growth of GaP1–xNx thin films by rf sputtering

“…In the second energy interval of 2.6 to 3.0 eV we observe a series of peaks which could be related to GaN inclusions in the film [6]. The incorporation of N-aggregates into the films cause structural disorder and may contribute to the broadening of the X-ray peaks of the samples.…”