Photoelectric properties of highly excited GaN:Fe epilayers, grown by modulation- and continuous-doping techniques

Bougrioua, Z.; Adnane, M.; Beaumont, B.; Gibart, P.; Malinauskas, T.; Neimontas, K.; Mekys, Algirdas; Storasta, J.; ̆iūnas, K. Jaras

doi:10.1016/j.jcrysgro.2006.11.015

Cited by 5 publications

(4 citation statements)

References 16 publications

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“…The space-charge region around dislocations leads to E g modulation and spatial separation of the carriers, therefore photo-or thermal activation is needed for overcoming the local potential barrier and recombination. Indeed, dislocation related, 10 meV barriers for photocurrent thermal activation were determined in conductive, non-intentionally doped GaN epilayers [5]. As the radius of the perturbed region approximately equals to the Debye length, λ D = (εε 0 kT /e 2 n) 1/2 , both temperature and illumination may influence the effective area around dislocations and modify the electrical activity of the charged dislocations.…”

Section: Resultsmentioning

confidence: 99%

Investigation of Optical Nonlinearities and Carrier Dynamics in In-Rich InGaN Alloys

et al. 2008

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We present experimental studies of nonequilibrium carrier dynamics in InGaN alloys with 70-90% content of In by using picosecond transient grating technique. The observed faster recombination rate in alloys with higher Ga content and formation of a thermal grating via a lattice heating, being more pronounced for layers with larger band gap, indicated that the main reason of the heating is not the excess energy of photons, but the defect density which increases with Ga content. A gradual decrease in carrier lifetime with excitation or with increasing temperature in 50-300 K range point out the role of potential barriers in carrier recombination.PACS numbers: 78.47.J-, 72.20.Jv

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Section: Resultsmentioning

confidence: 99%

Investigation of Optical Nonlinearities and Carrier Dynamics in In-Rich InGaN Alloys

et al. 2008

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“…[9] contradicts claiming that Fe-doping has increased the density of threading dislocations. Our previous study of modulation and continuously Fe-doped GaN epilayers on sapphire [10] has shown a good quality of the upper part of the modulation doped GaN epilayer, which has been indicated by long carrier lifetime (~1 ns) comparable to that in the undoped HVPE grown GaN [11]. A dominant non-linear (radiative) carrier recombination at low temperatures also manifested a comparatively low activity of dislocations, while sample resistivity remained high.…”

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confidence: 91%

Carrier dynamics in Fe‐doped GaN epilayers

Aleksiejūnas

Adnane

Bougrioua

et al. 2009

Phys. Status Solidi (c)

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Light induced transient grating technique is applied to study the recombination and transport properties of the excess carriers in the iron‐doped highly resistive GaN/sapphire epilayers, grown by MOCVD and doped using the modulation doping technique. Carrier lifetime, ambipolar diffusion coefficient, and threshold of the stimulated recombination are compared between Fe‐doped (NFe <1019 cm–3 and (0.5‐1)×1020 cm–3) and intentionally undoped epilayers. For comparison, undoped μ‐ELO GaN is also included into the study. In the Fe‐doped layers, we observe an increase in carrier lifetime, an increase in hole mobility, and a decrease in stimulated recombination efficiency. The lower‐doped layer exhibits the properties comparable to those of the high quality μ‐ELO GaN: carrier lifetime of 1.5 ns and diffusion coefficient of 1.9 cm2/s at 295 K; it is remarkable that the diffusion coefficient in the doped samples remains higher within the whole 30‐300 K temperature range. The enhanced mobility and lifetime in the iron‐doped samples we attribute to the inhibited electrical activity of the dislocations. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…The study of the two layer interacting configurations was continued in [11]. Recently, GaN thin layers were tested using the Hall effect [12] and the parameters were compared with optically obtained from near to the surface layers. The photo-measurements could extract information about the material from the surface regions where the light was absorbed and it was not important if the sample deeper inside, which has been formed with the buffer layer between sapphire substrate and GaN layer, had greater conductivity.…”

Section: Introductionmentioning

confidence: 99%

Hall Mobility Field Effect in Two Layer Conductivity Samples

et al. 2008

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Classical Hall mobility experimental setup was applied for samples with parallel plane (sandwich) variable conductivity layers. The measured effective Hall mobility strongly depends on applied electric field and does not characterise the real carrier mobility. Numerical modelling explains the effect as a consequence of electric field redistribution and lowering at Hall contacts. Measurement of carrier mobility in such structures is suggested.

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Photoelectric properties of highly excited GaN:Fe epilayers, grown by modulation- and continuous-doping techniques

Cited by 5 publications

References 16 publications

Investigation of Optical Nonlinearities and Carrier Dynamics in In-Rich InGaN Alloys

Investigation of Optical Nonlinearities and Carrier Dynamics in In-Rich InGaN Alloys

Carrier dynamics in Fe‐doped GaN epilayers

Hall Mobility Field Effect in Two Layer Conductivity Samples

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