Title: Raman Scattering Study of Lattice Vibrations in the Type-II Superlattice $\mathrm{InAs}/{\mathrm{InAs}}_{1-x}{\mathrm{Sb}}_x$

Abstract

The InAs/InAs_1-x Sb_x superlattice system distinctly differs from two well-studied superlattice systems GaAs/AlAs and InAs/GaSb in terms of electronic band alignment, common elements at the interface, and phonon spectrum overlapping of the constituents. This fact leads to the unique electronic and vibrational properties of the InAs/InAs_1-xSb_x system when compared to the other two systems. Here in this work, we report a polarized Raman study of the vibrational properties of the InAs/InAs_1-x Sb_x superlattices (SLs) as well as selected InAs_1-xSb_x alloys, all grown on GaSb substrates by either MBE or metalorganic chemical vapor deposition (MOCVD) from both the growth surface and cleaved edge. In the SL, from the (001) backscattering geometry, an InAs-like longitudinal optical (LO) mode is observed as the primary feature, and its intensity is found to increase with increasing Sb composition. From the (110) cleaved-edge backscattering geometry, an InAs-like transverse optical (TO) mode is observed as the main feature in two cross-polarization configurations, but an additional InAs-like “forbidden” LO mode is observed in two parallel-polarization configurations. The InAs_1-xSb_x alloys lattice matched to the substrate ( x_Sb ~ 0.09) grown by MBE are also found to exhibit the forbidden LO mode, implying the existence of some unexpected [001] modulation.more » However, the strained samples (x_Sb~ 0.35) grown by MOCVD are found to behave like a disordered alloy. The primary conclusions are (1) the InAs-like LO or TO mode can be either a confined or quasiconfined mode in the InAs layers of the SL or extended mode of the whole structure depending on the Sb composition. (2) InAs/InAs_1-xSb_x and InAs/GaSb SLs exhibit significantly different behaviors in the cleaved-edge geometry but qualitatively similar in the (001) geometry. (3) The appearance of the forbidden LO-like mode is a universal signature for SLs and bulk systems resulting from the mixing of phonon modes due to structural modulation or symmetry reduction.« less

Authors:

Liu, Henan ^[1]; Zhang, Yong ^[1]; Steenbergen, Elizabeth H. ^[2]; Liu, Shi ^[2]; Lin, Zhiyuan ^[2]; Zhang, Yong-Hang ^[2]; Kim, Jeomoh ^[3]; Ji, Mi-Hee ^[3]; Detchprohm, Theeradetch ^[3]; Dupuis, Russell D. ^[3]; Kim, Jin K. ^[4]; Hawkins, Samuel D. ^[4]; Klem, John F. ^[4]

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+ Show Author Affiliations

1. Univ. of North Carolina, Charlotte, NC (United States). Optical Science and Engineering Graduate Program and Dept. of Electrical and Computer Engineering
2. Arizona State Univ., Tempe, AZ (United States). Center for Photonics Innovation and School of Electrical, Computer and Energy Engineering
3. Georgia Inst. of Technology, Atlanta, GA (United States). Center for Compound Semiconductors and School of Electrical and Computer Engineering
4. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Publication Date:

Tue Sep 26 00:00:00 EDT 2017

Research Org.:

Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA); US Army Research Office (ARO)

OSTI Identifier:

1467461

Alternate Identifier(s):

OSTI ID: 1394874

Report Number(s):

SAND-2017-10149J
Journal ID: ISSN 2331-7019; PRAHB2; 657091

Grant/Contract Number:  

AC04-94AL85000; W911NF-10-1-0524; NA0003525

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review Applied

Additional Journal Information:

Journal Volume: 8; Journal Issue: 3; Journal ID: ISSN 2331-7019

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY