High-quality n-type aluminum gallium nitride thin films grown by interrupted deposition and in-situ thermal annealing

Wang, Wei; Gan, Xuewei; Xu, Yaxing; Wang, Ti; Wu, Hao; Liu, Chang

doi:10.1016/j.mssp.2014.11.010

Cited by 4 publications

(5 citation statements)

References 31 publications

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“…In our previous work, we have used Si Ga δ doping in Al 0.6 Ga 0.4 N alloys to increase the n-type carrier density30. Recent theoretical works predicted that the nanoscale (AlN) m /(GaN) n (m > n) SL could convert the valence-band maximum (VBM) from the crystal-field split-off hole to heavy hole band, leading to the increase of the transverse electric (TE) polarized light emission efficiency3132.…”

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confidence: 99%

“…Many works were concentrated on the doping in the superlattices (SLs) 23 24 25 26 27 28 29 , where a periodic oscillation of the valence band edge was created by the valence band discontinuity and innate polarization fields in Mg-doped AlGaN/GaN SLs, resulting in the accumulation of holes near the valance band edge close to the Fermi energy forming the so-called two-dimensional (2D) hole gases. In our previous work, we have used Si Ga δ doping in Al 0.6 Ga 0.4 N alloys to increase the n-type carrier density 30 . Recent theoretical works predicted that the nanoscale (AlN) m /(GaN) n (m > n) SL could convert the valence-band maximum (VBM) from the crystal-field split-off hole to heavy hole band, leading to the increase of the transverse electric (TE) polarized light emission efficiency 31 32 .…”

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confidence: 99%

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Experimental evidences for reducing Mg activation energy in high Al-content AlGaN alloy by MgGa δ doping in (AlN)m/(GaN)n superlattice

Wang

et al. 2017

Sci Rep

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P-type doping in high Al-content AlGaN alloys is a main challenge for realizing AlGaN-based deep ultraviolet optoelectronics devices. According to the first-principles calculations, Mg activation energy may be reduced so that a high hole concentration can be obtained by introducing nanoscale (AlN)5/(GaN)1 superlattice (SL) in Al0.83Ga0.17N disorder alloy. In this work, experimental evidences were achieved by analyzing Mg doped high Al-content AlGaN alloys and Mg doped AlGaN SLs as well as MgGa δ doped AlGaN SLs. Mg acceptor activation energy was significantly reduced from 0.378 to 0.331 eV by using MgGa δ doping in SLs instead of traditional doping in alloys. This new process was confirmed to be able to realize high p-type doping in high Al-content AlGaN.

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confidence: 99%

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confidence: 99%

Experimental evidences for reducing Mg activation energy in high Al-content AlGaN alloy by MgGa δ doping in (AlN)m/(GaN)n superlattice

Wang

et al. 2017

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“…Many studies have showed that heating treatments improve the crystal quality of semiconductor heterostructures. For example, in AlGaN thin films [10] and in InAs/GaAs QDs [14], a reduction in the density of threading dislocations after the heating process has been reported.…”

Section: Resultsmentioning

confidence: 99%

“…Dislocations introduce additional electronic states within the band gap, leading to nonradiative recombination phenomena. The application of a post-growth thermal annealing is a typical practicein order to improvethe material quality [10]. Two types of thermal treatments are normally applied in these materials: ex-situ and in situ ones.…”

Section: Introductionmentioning

confidence: 99%

“…Application of a conventional ex-situ technique to this a sample would have a very drastic and damaging effect on the quantum dots which are near the surface of our sample.The effect of these thermal annealing on the structural quality of semiconductor materialsis frequently measured indirectly, through the analysis of the optoelectronic properties of the material [11][12][13]. Some works have been published where the effect of the application of a thermal treatment tosemiconductor materials is analyzed by direct measurements in order to study the structural quality of the sample, for example, byconventionaltransmission electron microscopy [10,14]. These analyses provide information on the nanometer scale.…”

Section: Introductionmentioning

confidence: 99%

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Effect of an in-situ thermal annealing on the structural properties of self-assembled GaSb/GaAs quantum dots

Fernández‐Delgado

Herrera

Chisholm

et al. 2017

Applied Surface Science

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In this work, the effect of the application of a thermal annealing on the structural properties of GaSb/GaAs quantum dots (QDs) 1 is analyzed by aberration corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) 2 and electron energy loss spectroscopy (EELS) 3. Our results show that the GaSb/GaAs QDs are more elongated after the annealing, and that the interfaces are less abrupt due to the Sb diffusion. We have also found a strong reduction in the misfit dislocation density with the annealing. The analysis by EELS of a threading dislocation has shown that the dislocation core is rich in Sb. In addition, the region of the GaAs substrate delimited by the threading dislocation is shown to be Sb-rich as well. An enhanced diffusion of Sb due to a mechanism assisted by the dislocation movement is discussed. Keywords GaSb, quantum dot, scanning transmission electron microscopy, thermal annealing 1 Quantum dots 2 High-angle annular dark-field scanning transmission electron microscopy 3 Electron energy loss spectroscopy

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Atomic-column scanning transmission electron microscopy analysis of misfit dislocations in GaSb/GaAs quantum dots

et al. 2016

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The structural quality of GaSb/GaAs quantum dots (QDs) has been analyzed at atomic scale by aberration-corrected high-angle annular dark-field scanning transmission electron microscopy. In particular, we have studied the misfit dislocations that appear because of the high-lattice mismatch in the heterostructure. Our results have shown the formation of Lomer dislocations not only at the interface between the GaSb QDs and the GaAs substrate, but also at the interface with the GaAs capping layer, which is not a frequent observation. The analysis of these dislocations points to the existence of chains of dislocation loops around the QDs. The dislocation core of the observed defects has been characterized, showing that they are reconstructed Lomer dislocations, which have less distortion at the dislocation core in comparison to unreconstructed ones. Strain measurements using geometric phase analysis show that these dislocations may not fully relax the strain due to the lattice mismatch in the GaSb QDs.

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High-quality n-type aluminum gallium nitride thin films grown by interrupted deposition and in-situ thermal annealing

Cited by 4 publications

References 31 publications

Experimental evidences for reducing Mg activation energy in high Al-content AlGaN alloy by MgGa δ doping in (AlN)m/(GaN)n superlattice

Experimental evidences for reducing Mg activation energy in high Al-content AlGaN alloy by MgGa δ doping in (AlN)m/(GaN)n superlattice

Effect of an in-situ thermal annealing on the structural properties of self-assembled GaSb/GaAs quantum dots

Atomic-column scanning transmission electron microscopy analysis of misfit dislocations in GaSb/GaAs quantum dots

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