Gallium vacancies and the yellow luminescence in GaN

Neugebauer, Jörg; Walle, Chris G. Van de

doi:10.1063/1.117767

Cited by 1,100 publications

(763 citation statements)

References 12 publications

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“…The binding energy between between V Ga and Si Ga is considerably smaller (V Ga and Si Ga are only next-nearest neighbors) but still positive. 35 Recent ab initio calculations 10 predict also in InN a reduction of the defect formation energy for V In -O N complexes compared to the isolated case, and even stronger for the case of V In -3O N .…”

Section: E Vacancy-impurity Complexesmentioning

confidence: 98%

Identifying vacancy complexes in compound semiconductors with positron annihilation spectroscopy: A case study of InN

2011

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We present a comprehensive study of vacancy and vacancy-impurity complexes in InN combining positron annihilation spectroscopy and ab initio calculations. Positron densities and annihilation characteristics of common vacancy-type defects are calculated using density functional theory, and the feasibility of their experimental detection and distinction with positron annihilation methods is discussed. The computational results are compared to positron lifetime and conventional as well as coincidence Doppler broadening measurements of several representative InN samples. The particular dominant vacancy-type positron traps are identified and their characteristic positron lifetimes, Doppler ratio curves, and line-shape parameters determined. We find that indium vacancies (V In ) and their complexes with nitrogen vacancies (V N ) or impurities act as efficient positron traps, inducing distinct changes in the annihilation parameters compared to the InN lattice. Neutral or positively charged V N and pure V N complexes, on the other hand, do not trap positrons. The predominantly introduced positron trap in irradiated InN is identified as the isolated V In , while in as-grown InN layers V In do not occur isolated but complexed with one or more V N . The number of V N per V In in these complexes is found to increase from the near-surface region toward the layer-substrate interface.

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Section: E Vacancy-impurity Complexesmentioning

confidence: 98%

Identifying vacancy complexes in compound semiconductors with positron annihilation spectroscopy: A case study of InN

2011

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“…Theoretical calculations predict that Ga vacancies and related complexes form the predominant class of point defects in n-type GaN. 1,2 These defects have been experimentally observed by positron annihilation spectroscopy. 3,4 Ga vacancies are electrically active acceptors, and involved in the optical transition leading to the emission of yellow luminescence light.…”

mentioning

confidence: 99%

Thermal stability of isolated and complexed Ga vacancies in GaN bulk crystals

et al. 2001

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“…We thus believe that the increase (decrease) of the yellow line (MQW emission) intensity after the LLO is keenly related to the increased defect concentration at the bottom layer. [13][14][15] However, the blue-shift of the peak energy from the MQWs may not be explained by such a defect generation. To understand how the propagation of KrF photons into the GaN layer affects the creation of dislocations, we have studied the variation of the cone size and density as a function of the depth from interface with sapphire substrate.…”

Section: Resultsmentioning

confidence: 99%

Influence of laser lift-off on optical and structural properties of InGaN/GaN vertical blue light emitting diodes

et al. 2012

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The influences of the laser lift-off (LLO) process on the InGaN/GaN blue light emitting diode (LED) structures, grown on sapphire substrates by low-pressure metalorganic chemical vapor deposition, have been comprehensively investigated. The vertical LED structures on Cu carriers are fabricated using electroplating, LLO, and inductively coupled plasma etching processes sequentially. A detailed study is performed on the variation of defect concentration and optical properties, before and after the LLO process, employing high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM) observations, cathodoluminescence (CL), photoluminescence (PL), and high-resolution X-ray diffraction (HRXRD) measurements. The SEM observations on the distribution of dislocations after the LLO show well that even the GaN layer near to the multiple quantum wells (MQWs) is damaged. The CL measurements reveal that the peak energy of the InGaN/GaN MQW emission exhibits a blue-shift after the LLO process in addition to a reduced intensity. These behaviors are attributed to a diffusion of indium through the defects created by the LLO and creation of non-radiative recombination centers. The observed phenomena thus suggest that the MQWs, the active region of the InGaN/GaN light emitting diodes, may be damaged by the LLO process when thickness of the GaN layer below the MQW is made to be 5 μm, a conventional thickness. The CL images on the boundary between the KrF irradiated and non-irradiated regions suggest that the propagation of the KrF laser beam and an accompanied recombination enhanced defect reaction, rather than the propagation of a thermal shock wave, are the main origin of the damage effects of the LLO process on the InGaN/GaN MQWs and the n-GaN layer as well

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Gallium vacancies and the yellow luminescence in GaN

Cited by 1,100 publications

References 12 publications

Identifying vacancy complexes in compound semiconductors with positron annihilation spectroscopy: A case study of InN

Identifying vacancy complexes in compound semiconductors with positron annihilation spectroscopy: A case study of InN

Thermal stability of isolated and complexed Ga vacancies in GaN bulk crystals

Influence of laser lift-off on optical and structural properties of InGaN/GaN vertical blue light emitting diodes

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