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Journal ArticleDOI

Gallium vacancy and the residual acceptor in undoped GaSb studied by positron lifetime spectroscopy and photoluminescence

20 May 2002-Applied Physics Letters (American Institute of Physics)-Vol. 80, Iss: 21, pp 3934-3936
TL;DR: In this article, annealing studies were performed to study undoped p-type gallium antimonide materials and a 314 ps positron lifetime component was attributed to Ga vacancy (V-Ga) related defect.
Abstract: Positron lifetime, photoluminescence (PL), and Hall measurements were performed to study undoped p-type gallium antimonide materials. A 314 ps positron lifetime component was attributed to Ga vacancy (V-Ga) related defect. Isochronal annealing studies showed at 300 degreesC annealing, the 314 ps positron lifetime component and the two observed PL signals (777 and 797 meV) disappeared, which gave clear and strong evidence for their correlation. However, the hole concentration (similar to2x10(17) cm(-3)) was observed to be independent of the annealing temperature. Although the residual acceptor is generally related to the V-Ga defect, at least for cases with annealing temperatures above 300 degreesC, V-Ga is not the acceptor responsible for the p-type conduction. (C) 2002 American Institute of Physics.

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Citations
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Journal ArticleDOI
TL;DR: In this paper, the acceptors in liquid encapsulated Czochralski-grown undoped gallium antimonide (GaSb) were studied by temperature dependent Hall measurement and positron lifetime spectroscopy (PLS).
Abstract: Acceptors in liquid encapsulated Czochralski-grown undoped gallium antimonide (GaSb) were studied by temperature dependent Hall measurement and positron lifetime spectroscopy (PLS). Because of its high concentration and low ionization energy, a level at EV+34meV is found to be the important acceptor responsible for the p-type conduction of the samples. Two different kinds of VGa-related defects (lifetimes of 280ps and 315ps, respectively) having different microstructures were characterized by PLS. By comparing their annealing behaviors and charge state occupancies, the EV+34meV level could not be related to the two VGa-related defects.

35 citations

Journal ArticleDOI
TL;DR: In this paper, the positron lifetime spectroscopy (PAS) and the coincident Doppler broadening (CDB) technique were combined to identify Ca vacancy (V-Ga) related defects by combining the CDB measurements.

29 citations

Journal ArticleDOI
TL;DR: In this article, a green long persistent luminescence (LPL) phosphor Ca3Ga4O9:Tb3+/Zn2+ was prepared.

27 citations

Journal ArticleDOI
TL;DR: Zhang et al. as mentioned in this paper found that the Ga atoms from the diffusion sources suppressed the formation of the high-concentration surface diffusion fronts in Zn profiles, thus converting the kink-and-tail-shaped profile to the box-shape profile.
Abstract: Different diffusion sources were used to study Zn diffusion in n-GaSb. We found that the Ga atoms from the diffusion sources suppressed the formation of the high-concentration surface diffusion fronts in Zn profiles, thus converting the kink-and-tail-shaped profile to the box-shaped profile. Our analysis demonstrated that both the surface and the tail regions in the kink-and-tail profiles showed high-quality regularities. The analysis also revealed that the formation mechanism of the box profiles is the same as that of the tail region of the kink-and-tail profiles. The similarities of the photoluminescence signals between the main region of the box profiles and the tail region of the kink-and-tail profiles substantiated our findings.

16 citations

Journal ArticleDOI
TL;DR: In this article, the authors compared the results of Bracht et al. and Weiler and Mehrer (Weiler D, Mehrer H 1984 Phil. Mag. Appl. 89 5393) with the results obtained by Bracht and Nicols.
Abstract: The recent results for the self-diffusivities, D(Ga) and D(Sb), of Ga and Sb in GaSb obtained by Bracht et al (Bracht H, Nicols S P, Walukjewicz W, Silveira J P, Briones F and Haller E E 2000 Nature 408 69 and Bracht H, Nicols S P, Haller E E, Silveira J P and Briones F 2001 J. Appl. Phys. 89 5393) are compared and related to the earlier measurements by Weiler and Mehrer (Weiler D and Mehrer H 1984 Phil. Mag. A 49 309). It is proposed that the differences between the two sets of data are due to higher concentrations of hydrogen impurity in the samples of Weiler and Mehrer. The experimental evidence indicates that the diffusion mechanisms associated with D(Ga) and D(Sb) both have two parallel mechanisms. For D(Ga) the native defects involved are the Frenkel pair, GaiVGa, and the Ga vacancy, VGa. For D(Sb) one mechanism is due to the defect pair SbiVGa and the second to either the vacancy pair VGaVSb or the triple defect VGaGaSbVGa. It is proposed that the mobilities of all these defects, excepting GaiVGa, are enhanced in the presence of hydrogen as an impurity in the GaSb lattice. On this basis the differences in the data obtained by Bracht et al and Weiler and Mehrer can be reconciled. It is also shown that measured free hole concentrations identify Ga2−Sb as the residual acceptor in GaSb and that undoped GaSb is intrinsic at diffusion anneal temperatures.

13 citations

References
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Journal ArticleDOI
TL;DR: In this article, the influence of direction of growth, melt composition and growth speed upon the relative occurrence of the residual acceptor centers in melt-grown GaSb single crystals was studied.

142 citations

Journal ArticleDOI
TL;DR: A doubly ionizable acceptor (EA = 34.5 meV, EC = 102 meV), which is responsible for the hole concentration in undoped GaSb, is identified by photoluminescence experiments at 2 K.
Abstract: A doubly ionizable acceptor (binding energies of EA = 34.5 meV, EC = 102 meV), which is responsible for the hole concentration in undoped GaSb, is identified by photoluminescence experiments at 2 K. Growth experiments, using nonstoichiometric melts, show that this acceptor is connected with a lack of antimony in the crystals. Experimental photoluminescence data, concerning the free exciton recombination at 810 meV and an emission line at 795.5 meV (possibly a bound exciton) as well as new phonon satellites, are presented. Finally, photoconductance measurements at the same samples give further information about excitons in GaSb. Der doppelt ionisierbare Akzeptor (Bindungsenergien EA = 34,5 meV und EC = 102 meV), der die hohe Locherkonzentration in undotiertem GaSb verursacht, wird durch Photolumineszenzexperimente bei 2 K identifiziert. Untersuchungen an Kristallen, die aus Schmelzen mit unterschiedlichem Antimongehalt gezogen wurden, zeigen, das dieser Akzeptor auf einem Mangel an Antimon im Kristall beruht. Weiterhin wird uber experimentelle Photolumineszenzdaten berichtet, die sowohl die Rekombination des freien Exzitons bei 810 meV und eine Emissionslinie bei 795,5 meV (wahrscheinlich ein gebundenes Exziton) als auch neue Phononensatelliten betreffen. Schlieslich geben Photoleitfahigkeitsmessungen an den gleichen Proben weitere Information uber Exzitonen in GaSb.

98 citations

Journal ArticleDOI
TL;DR: In this article, the p-type nature of GaSb is due to lattice defects rather than to impurities, and the best sample measured had a hole concentration of 9.2 × 1015cm−3 and a Hall mobility of 5230 cm2/V sec at 77°K.

89 citations

Journal ArticleDOI
TL;DR: A detailed analysis of photo-luminescence spectroscopy (PL) on undoped and Te-and Zn-doped samples of high-quality GaSb is presented in this article.
Abstract: A detailed analysis of PhotoLuminescence spectroscopy (PL) on undoped and Te- and Zn-doped samples of high-quality GaSb is presented. Temperature variations of PL peak position and intensity have been used to find the origin of various transitions. The PL peaks of undoped samples have been assigned to unintentional impurities, native defects and excitons bound to the defect. The zinc- and tellurium-related peaks have been identified and the effect of doping concentration on their position and PL efficiency have been studied.

30 citations

Journal ArticleDOI
TL;DR: In this paper, the positron lifetime measurements were performed on the as-grown sample at temperature varying from 15 K to 297 K, and a positron trapping center having a characteristic lifetime of 317 ps was identified as the neutral positron-related defect.
Abstract: Defects in p-type Zn-doped liquid-encapsulated Czochralski\char21{}grown GaSb were studied by the positron lifetime technique. The lifetime measurements were performed on the as-grown sample at temperature varying from 15 K to 297 K. A positron trapping center having a characteristic lifetime of 317 ps was identified as the neutral ${V}_{\mathrm{Ga}}$-related defect. Its concentration in the as-grown sample was found to be in the range of ${10}^{17}\char21{}{10}^{18} {\mathrm{cm}}^{\ensuremath{-}3}.$ At an annealing temperature of $300\ifmmode^\circ\else\textdegree\fi{}\mathrm{C},$ the ${V}_{\mathrm{Ga}}$-related defect began annealing out and a new defect capable of trapping positrons was formed. This newly formed defect, having a lifetime value of 379 ps, is attributed to a vacancy\char21{}Zn-defect complex. This defect started annealing out at a temperature of $580\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}.$ A positron shallow trap having binding energy and concentration of 75 meV and ${10}^{18} {\mathrm{cm}}^{\ensuremath{-}3},$ respectively, was also observed in the as-grown sample. This shallow trap is attributed to positrons forming hydrogenlike Rydberg states with the ionized dopant acceptor Zn.

23 citations