Lateral composition modulation in InAs/GaSb superlattices

Stokes, D. W.; Forrest, R. L.; Li, J. H.; Moss, S. C.; Nosho, B. Z.; Bennett, B. R.; Whitman, L. J.; Goldenberg, M.

doi:10.1063/1.1529291

Cited by 13 publications

(5 citation statements)

References 35 publications

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“…The^10 Å variation in L SL is due to a splitting in the satellite peaks, which indicates that there are two or more discrete superlattice periods formed along the growth direction. This was evident in the XSTM images taken of the entire vertical height of the structure [14] (not shown), where the undulations did not become regular until after about 40 periods, and became irregular after 80 periods. The lateral wavelength, L LCM ¼ 554 AE 3 A; is similar in magnitude to the 100 to 400 Å wavelengths reported for other LCM systems, where it is generally found that the lateral and undulating wavelengths are identical; however, this is not the case for this sample.…”

Section: Discussionmentioning

confidence: 89%

X-ray diffraction analysis of lateral composition modulation in InAs/GaSb superlattices intended for infrared detector applications

Stokes

Forrest

et al. 2003

IEE Proc., Optoelectron.

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Lateral compositional modulation in a ðInAsÞ 13 =ðGaSbÞ 13 superlattice grown by molecular beam epitaxy for infrared detector applications has been investigated using highresolution X-ray diffraction. X-ray diffraction reciprocal space maps exhibit distinct lateral satellite peaks about the vertical superlattice peaks; however, the pattern is tilted with respect to the (001) direction. This tilt is directly related to the stacking of the layers as revealed by cross-sectional scanning tunnelling microscopy (XSTM) images. XSTM shows the morphology of the structure to consist of InAs-and GaSb-rich regions with a modulation wavelength of , 1200 Å and a lateral composition wavelength of 554 AE 3 A: The modulation only occurs along one in-plane direction, resulting in InAs 'nanowires' along the [110] direction, which are several microns long. The possible causes of the lateral composition modulation and its impact on device performance are discussed.

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Section: Discussionmentioning

confidence: 89%

X-ray diffraction analysis of lateral composition modulation in InAs/GaSb superlattices intended for infrared detector applications

Stokes

Forrest

et al. 2003

IEE Proc., Optoelectron.

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“…Of particular interest are materials systems that spontaneously self-organize with a significant degree of regularity, since this periodicity can impact the electronic band structure and consequently, materials properties and device performance. Lateral composition modulation (LCM) has been reported in strained alloy systems such as bulk AlInAs and GaInP epilayers [6][7][8], as well as in intentionally grown short period superlattices such as GaP/InP, AlAs/InAs, GaAs/InAs, and InAs/GaSb [9][10][11][12]. CuPt ordering as observed in GaInP [2], GaAsP [3], GaAsSb, [4], and InAsSb [5], to microscopic dimensions on the order of ~50 nm, e.g.…”

Section: Introductionmentioning

confidence: 99%

Self-Organized Superlattices in GaInAsSb Grown on Vicinal Substrates

2003

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Self-organized superlattices are observed in GaInAsSb epilayers grown lattice matched to vicinal GaSb substrates. The natural superlattice (NSL) is oriented at a slight angle of about 4" with respect to the vicinal (001) GaSb substrqte. This vertical composition modulation is detected at the onset of growth. Layers in the NSL are continuous over the lateral extent of the substrate. Furthermore, the NSL persists throughout several microns of deposition. The NSLs have a period ranging fiom 10 to 30 nm, whidh is dependent on deposition temperature and GaInAsSb alloy composition. While the prinbple driving force for this type of phase separation is chemical, the mechanism for the self-orgdzed microstructure is related to local strains associated with surface undulations. By using a substrate with surface undulations, the tilted NSL can be induced in layers with alloy comflositions that normally do not exhibit this selforganized microstructure under typical growth conditions. These results underscore the complex interactions between compositional and morphological perturbations.

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“…Recently, lateral composition modulation (LCM) was observed in InAs/GaSb superlattices 8,9 . LCM, which refers to the formation of phase-separated, periodic structures perpendicular to the growth direction 10 , induces changes in the physical properties of the material, i.e., The nanostructures self-organized via lateral composition modulation in 140 period (InAs)13/(GaSb)13 superlattices grown by molecular beam epitaxy have been studied by high-resolution x-ray diffraction and infrared absorption.…”

Section: Introductionmentioning

confidence: 99%

Optical and Structural Properties of InAs/GaSb Nanostructures

Stokes

Forrest

et al. 2003

MRS Proc.

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The nanostructures self-organized via lateral composition modulation in 140 period (InAs) 13 /(GaSb) 13 superlattices grown by molecular beam epitaxy have been studied by highresolution x-ray diffraction and infrared absorption. Three samples were analyzed in this study; two with lateral composition modulation and one without. X-ray reciprocal space map scans were taken to determine the average morphology of the modulated structures. Both vertical and lateral satellite peaks were observed for the samples with composition modulation, indicating the formation of two-dimensional nanowire arrays. The vertical wavelength measured for the two samples was twice the period intended by the growers. This is due to the face-centered cubic type stacking of the nanowires. Infrared absorption spectra of these two samples were compared to the spectra of the sample with no lateral composition modulation. Transitions involving the heavy-and light-hole bands in the GaSb hole quantum well and the electron subbands of the InAs electron quantum well were not evident for the samples with lateral composition modulation, indicating that the nanostructure of the lateral composition modulation affects the optical response of the sample, which is important for optoelectronic device applications.

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Lateral composition modulation in InAs/GaSb superlattices

Cited by 13 publications

References 35 publications

X-ray diffraction analysis of lateral composition modulation in InAs/GaSb superlattices intended for infrared detector applications

X-ray diffraction analysis of lateral composition modulation in InAs/GaSb superlattices intended for infrared detector applications

Self-Organized Superlattices in GaInAsSb Grown on Vicinal Substrates

Optical and Structural Properties of InAs/GaSb Nanostructures

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