Photoluminescence properties of GaN with dislocations induced by plastic deformation

Abstract

Fresh (a/3)½1120 dislocations on the ð1 100Þ prismatic plane were introduced into GaN bulk crystals by plastic deformation at 950-1000°C. In photoluminescence studies at 11 K, the near-band-edge (3.48 eV) luminescence intensity decreased remarkably in the deformed GaN, which was attributed to the introduction of high-density nonradiative recombination centers during plastic deformation. The yellow-band luminescence (2.22 eV) decreased due to plastic deformation, while several luminescence bands centered at 1.79, 1.92, and 2.4 eV developed. The dependence of PL features on deformation and annealing suggests that yellow luminescence is not related to the native structure of edge dislocations in GaN.

Local current conduction due to edge dislocations in deformed GaN studied by scanning spreading resistance microscopy

“…The introduced shear strain was 5%. Detailed procedures of the deformation tests [16] and photoluminescence measurements [17,18] for the deformed samples have been reported elsewhere. After the deformation, some of the samples were sliced parallel to the glide plane followed by mechanical and ionic polishing, and observed by transmission electron microscopy (TEM)…”

Optical properties of fresh dislocations in GaN

“…Fig. 1 shows the PL spectra of as-grown GaN crystals and GaN crystals deformed at 950 1C, and GaN crystal subsequently annealed at 950 1C after 30% deformation, measured at 11 K. PL spectra in the 1.4-2.9 eV photon energy range enlarged 100 times [2].…”

“…Here we review our recent results on optical properties of dislocations freshly induced into GaN crystals by plastic deformation [2][3][4].…”

In-Situ Analysis of Optoelectronic Properties of Semiconductor Nanostructures and Defects in Transmission Electron Microscopes

“…Also, threading dislocations, i.e., dislocations lying on pyramidal planes with b = 1/3<1120> (Albrecht et al, 2008) and those on prismatic planes with b = 1/3<1120> or 1/3<1121> (Yamamoto et al, 2003), act as non-radiative recombination center. Even though the threading dislocations have a smaller recombination activity in comparison with the misfit dislocations (Yamamoto et al, 2003), they reduce overall luminescence intensities (Yonenaga et al, 2006). The diffusion length of minority carriers around a dislocation is estimated (Yamamoto et al, 2003, Nakaji et al, 2005, Ino & Yamamoto, 2008, and it is smaller in comparison with the other semiconductors; e.g., about 200 nm, 150 nm, and 60 nm, respectively, for non-doped, Mg-doped (1x10 17 cm -3 ), and Sidoped (3x10 18 cm -3 ) GaN, even at low temperatures.…”

“…5 and 6). This characteristic of ZnO may be an advantage over GaN, since all emissions in GaN are suppressed when dislocations are introduced even at elevated temperatures (Yonenaga et al, 2006), as well as at room temperature. (Kucheyev et al, 2000).…”