I2basal plane stacking fault in GaN: Origin of the 3.32 eV luminescence band

Abstract

We investigate the 3.32 eV defect-related emission band in GaN correlating transmission electron microscopy and spatially and spectrally resolved cathodoluminescence at low temperature. The band is unambiguously associated with basal plane stacking faults of type I 2 , which are a common defect type in semi-and nonpolar GaN grown on foreign substrates. We ascribe the luminescence to free-to-bound transitions. The suggested intrinsic acceptors involved have an ionization energy of ≈0.17 eV, and are located at the I 2 -type basal plane stacking faults.

Correlation between Si doping and stacking fault related luminescence in homoepitaxial m-plane GaN

“…Additionally, three rather narrow emission lines with relative intensities depending on samples and positions have been found in the region of defect luminescence: at $3.42 (SF1), at $3.39 (SF2), and at $3.37 eV (SF3). The emission within the range of 3.39-3.42 eV was previously identified as being related to BSF, [7][8][9][10]16 while the 3.37 eV peak is close to the feature at 3.34 eV related to PSFs in heteroepitaxial a-plane GaN. 7 The origin of these lines is in accordance with these identifications as it is confirmed by spatially resolved CL data presented in Fig.…”

“…3. However, as already mentioned above, we have not found the SF-related luminescence in the samples with Si doping exceeding 10 18 cm À3 In spite of this, we can observe SFs in SEM images and also in CL images, albeit as non-radiative regions in this case and in the layers. To illustrate our observations, an SEM image together with panchromatic CL (PCL) mapping for the layer doped with Si concentration of 2.4 Â 10 18 cm À3 is shown in Figs. 3(a) and 3(b), respectively.…”

“…SFs of different geometries can sometimes be optically active and may lead to several features in the luminescence spectra in the region of 3.29-3.41 eV as was reported for the heteroepitaxial undoped GaN grown in a-and m-directions. [7][8][9][10] In mature undoped or n-type doped polar GaN layers, the SF density is low and can hardly be considered as a problem for electronic and optoelectronic devices. Correspondingly, in such samples, usually no SF-associated emission is present in the luminescence spectra.…”

On the luminescence of freshly introduced a-screw dislocations in low-resistance GaN

“…The luminescence of different SF types in GaN has been studied in considerable detail [36][37][38]. Accord ing to the data obtained, three stacking faults existing in wurtzite, usually denoted as I 1 , I 2 , E, yield emission lines differing in energy in the range from 3.29 to 3.42 eV [36].…”

Luminescence associated with stacking faults in GaN

“…As first pointed out by Rieger et al [21] and Rebane et al [22], these WZ/ZB heterostructures may be pictured as ZB quantum wells (QWs) in a WZ matrix leading to emission at energies lower than for excitons in the bulk WZ phase, which in GaN is found at 3.478 eV [23]. While transitions associated with excitons bound to BSFs of the intrinsic I 1 type are well established to lie in the range of 3.40 to 3.42 eV [6,11,[24][25][26][27][28][29], there are fewer reports on luminescence lines associated with BSFs of the intrinsic I 2 type [5,[30][31][32]. Only recently, we reported emission peaks related to extrinsic BSFs [32], and Jacopin et al [33] observed luminescence lines associated with ZB segments.…”