Spectral ellipsometry of GaSb: Experiment and modeling

Muñoz, Martı́n; Wei, Kaya; Pollak, Fred H.; Freeouf, J. L.; Charache, G.W.

doi:10.1103/physrevb.60.8105

Cited by 57 publications

(41 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Such a mechanism was also found in quantum-dot structures, 40 where carriers in the wetting layer with low kinetic energy (near the Ŵ point) are scattered into quantum dots. (Table II)a r e obtained as 794.8 ± 0.03 meV (GaSb) and 332.8 ± 0.3meV (In 0.53 Ga 0.47 As), which agree with the reported values of 796 meV (GaSb) 24 and 329.6m e V( I n 0.53 Ga 0.47 As). 26 The identified feature is also confirmed by observing an onset of the yield (a change in the slope).…”

Section: /∇supporting

confidence: 88%

Direct observation of spin-orbit splitting and phonon-assisted optical transitions in the valence band by internal photoemission spectroscopy

Lao

Perera

et al. 2013

Phys. Rev. B

View full text Add to dashboard Cite

We employ internal photoemission spectroscopy to directly measure the valence-band Van Hove singularity, and identify phonons participating in indirect intervalence-band optical transitions. Photoemission of holes photoexcited through transitions between valence bands displays a clear and resolvable threshold, unlike previous reports of interband critical points which become obscure in doped materials. We also demonstrate the enhancement of optical phonon-assisted features primarily contributing to the photoemission yield. This result is evidence of the relaxation of photoexcited hot holes through intravalence-band scatterings in heterojunctions, which contrast with intervalence-band scatterings in bulks.

show abstract

Section: /∇supporting

confidence: 88%

Direct observation of spin-orbit splitting and phonon-assisted optical transitions in the valence band by internal photoemission spectroscopy

Lao

Perera

et al. 2013

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

“…As absorption coefficient decreases with increasing wavelength, 6 It is apparent from Figures 1 to 6 that the bulk coupled mode-to-SSCR scattering intensity ratio is dependent on both excitation wavelength and carrier concentration. In general, the bulk coupled mode-to-SSCR scattering intensity ratio increases with increasing excitation wavelength and n e , as expected since Raman probe depth increases with increasing wavelength and SSCR width generally decreases with increasing electron concentration.…”

Section: 11mentioning

confidence: 99%

“…For radiation with wavelengths shorter than ≈600 nm, the absorption coefficient of radiation in GaSb increases significantly and continues to increase as wavelength decreases. 6 Hence, for scattering excitation wavelengths of ≈532 nm or shorter, observed scattering from GaSb results largely from the SSCR and it is difficult, if not impossible, to probe bulk material properties, particularly for epilayers with moderate to low doping levels (and concomitant large SSCR width). Such a situation can lead to obvious problems for spectral interpretation.…”

Section: 3mentioning

confidence: 99%

“…In general, the bulk coupled mode-to-SSCR scattering intensity ratio increases with increasing excitation wavelength and n e , as expected since Raman probe depth increases with increasing wavelength and SSCR width generally decreases with increasing electron concentration. These trends can be used to estimate the SSCR width, d dep , using a relatively simple model in which a two layer system with an abrupt junction is assumed: 6 In Fig. 8, Raman probe depth is plotted to help illustrate trends and is not meant to indicate the depth limit from which signal is detected.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Raman Spectroscopy of n-Type and p-Type GaSb with Multiple Excitation Wavelengths

2007

View full text Add to dashboard Cite

The interpretation of Raman spectra of GaSb can be complicated by the presence of a so-called surface space charge region (SSCR), resulting in an inhomogeneous near-surface Raman scattering environment. To fully interpret Raman spectra, it is important to have an understanding of the SSCR profile relative to the Raman probe depth. However, a priori determination of even the actual SSCR width is not always possible for GaSb under a wide range of doping levels. The primary objective of this report is to provide a convenient reference to aid in the determination of relative contributions to an observed GaSb Raman spectrum of SSCR scattering and bulk scattering for a range of excitation wavelengths, doping levels, and SSCR widths and types. Hence, Raman spectra of both n-type and p-type doped GaSb epilayers were obtained using 488 nm, 514.5 nm, 647.1 nm, and 752.55 nm excitation radiation. Both n-type and p-type doped GaSb epilayers were selected for investigation because these layers exhibit the two different SSCR types that are typically encountered with as-grown GaSb and relatedThe Lincoln Laboratory portion of this work was sponsored by the Department of Energy (DOE), under Air Force contact number FA8721-05-C-0002. The opinions, interpretations, conclusions and recommendations are those of the authors and are not necessarily endorsed by the United States Government.2 materials. A range of doping levels were examined for each doping type so as to examine the effects of a varying SSCR width on the observed spectra. A secondary objective of this report is to demonstrate the performance of a spectroscopic system based on 752.55 nm excitation that is sensitive to bulk carrier properties in n-type and p-type doped GaSb epilayers over a wide doping range, unlike visible wavelength-based optical systems. Index Headings:GaSb; Raman spectroscopy; surface space charge region; depletion layer; accumulation layer; n-type doping, p-type doping * Corresponding author: e-mail: jmaslar@nist.govPhone: 301-975-4182 INTRODUCTIONGaSb and related alloy semiconductors, e.g., GaInAsSb and GaInSb, are of interest for mid-infrared sources and detectors and low-power, high-speed electronic devices. 1-3Characterization of these materials at various stages of device fabrication is critical to fabrication process development and a variety of metrologies have been employed for this purpose, [1][2][3] including Raman spectroscopy. 1,3 Raman spectroscopy can potentially be used to probe numerous materials properties of semiconductor materials, including crystal quality, alloy composition, and carrier concentration and mobility. 4 Although Raman spectroscopy is a potentially useful technique for characterizing a variety of GaSb material properties, the interpretation of Raman spectra of GaSb and related materials can be complicated by the inhomogeneous nature of the near-surface Raman scattering environment. Compound semiconductor materials exhibit a so-called surface space-charge 3 region (SSCR) that develops because of the presence of charge-...

show abstract

“…3 deduced values of R 1 are in reasonable agreement with a simple effective mass/k"p calculation. 1,12,[13][14][15] The approach of Djurišić and Li is particularly suspect. [8][9][10] They have completely ignored excitonic effects at both the E 0 /E 0 ϩ⌬ 0 and E 1 /E 1 ϩ⌬ 1 CPs.…”

mentioning

confidence: 99%

Response to “Comment on ‘Optical properties of CdTe1−xSx (0⩽x⩽1): Experiment and modeling’ ” [J. Appl. Phys. 88, 2172 (2000)]

Pollak

2000

Journal of Applied Physics

Self Cite

View full text Add to dashboard Cite

This communication is a response to the Comment on “Optical properties of CdTeS: Experiment and modeling” by A. B. Djurišić and E. H. Li. The shortcomings of a number of schemes to model the optical constants of diamond- and zincblende-type semiconductors, which do not include continuum exciton effects at either the E0, E0+Δ0 or E1, E1+Δ1 critical points (CPs), are discussed. The Holden model, which has been used to fit the CdTeS data, does include these effects, making it possible to extract important parameters, such as the binding energy of the exciton associated with the E1, E1+Δ1 CPs, not deduced by the other approaches.

show abstract

Spectral ellipsometry of GaSb: Experiment and modeling

Cited by 57 publications

References 28 publications

Direct observation of spin-orbit splitting and phonon-assisted optical transitions in the valence band by internal photoemission spectroscopy

Direct observation of spin-orbit splitting and phonon-assisted optical transitions in the valence band by internal photoemission spectroscopy

Raman Spectroscopy of n-Type and p-Type GaSb with Multiple Excitation Wavelengths

Response to “Comment on ‘Optical properties of CdTe1−xSx (0⩽x⩽1): Experiment and modeling’ ” [J. Appl. Phys. 88, 2172 (2000)]

Contact Info

Product

Resources

About