On GaN Crystallization by Ammonothermal Method

Dwiliński, R.; Baranowski, J. M.; Kamińska, M.; Doradziński, R.; Garczyński, J.; Sierzputowski, L.

doi:10.12693/aphyspola.90.763

Cited by 78 publications

(60 citation statements)

References 2 publications

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“…In the mid-1990s Dwiliński et al had first demonstrated that it is possible to get crystalline GaN by a chemical reaction between gallium and ammonia, in the presence of alkali metal amides (LiNH 2 or KNH 2 ) as mineralizers [49,50]. GaN was synthesized using supercritical ammonia and metallic gallium, at the temperature of 500…”

Section: Ammonothermal Methodsmentioning

confidence: 99%

Atomistic simulation of damage production by atomic and molecular ion irradiation in GaN

Ullah

Kuronen

Nordlund

et al. 2012

Journal of Applied Physics

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Gallium nitride (GaN) has emerged as one of the most important semiconductors in modern technology. GaN-based device technology was mainly pushed forward by invention of p-type doping and the successful fabrication of light emitting diodes (LEDs) and laser diodes (LDs). Intensive studies in the last 20 years on GaN have significantly advanced the understanding of the properties and have expanded the range of practical applications. Beside basic lighting, current applications of GaN include high-power and high temperature electronics, microwave, optoelectronic devices, and so on.The successful production of optical devices demands efficient tuning of charge carrier lifetime where defect engineering plays a vital role. During growth, varying the level of recombination centers is difficult, whereas ion irradiation can do this job efficiently on a final product. On the other hand, during doping, undesirable defects can also be produced and epitaxial GaN is known to have a highly defective structure. Thus, having both positive and negative aspects, it is very important to have a detailed understanding of irradiation-induced defects.To explain experimental findings, atomic level understanding is necessary, but it is not always possible to have an atomistic view of defect dynamics in experiments. Some damage build-up studies by single ions have been reported in the literature, but not many by molecular ions. In this thesis, the irradiation of GaN by single and molecular ions by the means of atomistic simulations was studied. The irradiation response of both bulk and nano-structured GaN system were studied. For bulk studies, all projectiles were irradiated having the same energy per mass. The damage by molecular ions showed strong dynamic annealing. No non-linearity had been observed in the total number of point defects between single and molecular ions. On the other hand, molecular ions produce larger clusters of point defects than single ions. These large defect clusters can be one of the mechanisms of the experimentally observed faster carrier decay time for molecular projectiles. Defects were mostly concentrated at the surface and near-surface regions, which is also evident from experiments.ii Comparison between a similar mass single ion and a molecular ion show that a single ion produced more defect clusters than molecular ions. This suggests that heavy ions are even more efficient than similar mass cluster ions to quench the carrier lifetime.

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Section: Ammonothermal Methodsmentioning

confidence: 99%

Atomistic simulation of damage production by atomic and molecular ion irradiation in GaN

Ullah

Kuronen

Nordlund

et al. 2012

Journal of Applied Physics

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“…It is also known that various bulk binary nitrides are formed from the metal in supercritical ammonia using an ammonobasic mineralizer (see paragraph Nitrides), from technological point of view, the most interesting examples currently being the semiconductors GaN [77] and AlN [78]. Recent research in ammonobasic conditions indicates that the binary nitrides are formed via ternary amides functioning as intermediate species [67,79] following the assumed reaction Equation (6 4 ] was proposed as possible intermediate compound [79] and was indeed recently found to crystallize in two modifications in the hot zone of the autoclave [67].…”

Section: Ammonobasic Systemsmentioning

confidence: 99%

Chemistry of Ammonothermal Synthesis

2014

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Ammonothermal synthesis is a method for synthesis and crystal growth suitable for a large range of chemically different materials, such as nitrides (e.g., GaN, AlN), amides (e.g., LiNH 2 , Zn(NH 2 ) 2 ), imides (e.g., Th(NH) 2 ), ammoniates (e.g., Ga(NH 3 ) 3 F 3 , [Al(NH 3 ) 6 ]I 3 · NH 3 ) and non-nitrogen compounds like hydroxides, hydrogen sulfides and polychalcogenides (e.g., NaOH, LiHS, CaS, Cs 2 Te 5 ). In particular, large scale production of high quality crystals is possible, due to comparatively simple scalability of the experimental set-up. The ammonothermal method is defined as employing a heterogeneous reaction in ammonia as one homogenous fluid close to or in supercritical state. Three types of milieus may be applied during ammonothermal synthesis: ammonobasic, ammononeutral or ammonoacidic, evoked by the used starting materials and mineralizers, strongly influencing the obtained products. There is little known about the dissolution and materials transport processes or the deposition mechanisms during ammonothermal crystal growth. However, the initial results indicate the possible nature of different intermediate species present in the respective milieus. A Alkali or alkaline-earth metal, A(1) = alkali metal, A(2) = alkaline-earth metal B Further metal, might be main group metal, transition or rare-earth metal M Transition metal, excluding Sc, Y, La R Rare-earth metal, Sc, Y, La-Lu X Halide E Other main group element

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“…The samples were obtained by AMMONO method described elsewhere [2]. The AMMONO technique allowed to grow nitride crystals at relatively low temperature and pressure conditions (our crystals were obtained at temperatures not exceeding 5500C and pressures below 5 kbar).…”

Section: Ammono Gan Crystalsmentioning

confidence: 99%

Some Optical and Epr Properties of Strain-Free GaN Crystals Obtained by Ammono Method

et al. 1997

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AMMONO GaN is grown spontaneously from ammonia solution in form of regular, well shaped, few micrometer crystals. Photoluminescence spectra of these crystals are characterized by fixed positions of very narrow exciton lines (FWHM down to 1 meV), where free excitons A, B, C, resolved two donor bound excitons and acceptor bound exciton are visible. Fixed position of exciton lines is in contrast to small changes of line energies which have been always observed for epitaxial GaN 1ayers because of strain present in them. Free electron concentration of ΑΜΜOΝO GaN is less than few times 101 5 cm-3 , as estimated from EPR signal of shallow donor. The above-mentioned facts qualified these crystals as state of the art strain-free, model material for basic parameter measurements of GaN. In this work, results of PL and EPR measurements performed on ΑΜΜOΝO GaN crystals are presented and discussed..

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On GaN Crystallization by Ammonothermal Method

Cited by 78 publications

References 2 publications

Atomistic simulation of damage production by atomic and molecular ion irradiation in GaN

Atomistic simulation of damage production by atomic and molecular ion irradiation in GaN

Chemistry of Ammonothermal Synthesis

Some Optical and Epr Properties of Strain-Free GaN Crystals Obtained by Ammono Method

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