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Maximizing Tensile Strain in Germani...

Sanchez Perez, Jose Roberto.

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Maximizing Tensile Strain in Germanium Nanomembranes for Enhanced Optoelectronic Properties.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Maximizing Tensile Strain in Germanium Nanomembranes for Enhanced Optoelectronic Properties./
Author:	Sanchez Perez, Jose Roberto.
Description:	120 p.
Notes:	Source: Dissertation Abstracts International, Volume: 76-06(E), Section: B.
Contained By:	Dissertation Abstracts International76-06B(E).
Subject:	Materials science. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3680587
ISBN:	9781321526608

Maximizing Tensile Strain in Germanium Nanomembranes for Enhanced Optoelectronic Properties.
Sanchez Perez, Jose Roberto.

Maximizing Tensile Strain in Germanium Nanomembranes for Enhanced Optoelectronic Properties. - 120 p.

Source: Dissertation Abstracts International, Volume: 76-06(E), Section: B.

Thesis (Ph.D.)--The University of Wisconsin - Madison, 2015.

This item must not be sold to any third party vendors.

Silicon, germanium, and their alloys, which provide the leading materials platform of microelectronics, are extremely inefficient light emitters because of their indirect fundamental energy band gap. This basic materials property has so far hindered the development of group-IV photonic-active devices, including light emitters and diode lasers, thereby significantly limiting our ability to integrate electronic and photonic functionalities at the chip level. Theoretical studies have predicted that tensile strain in Ge lowers the direct energy band gap relative to the indirect one, and that, with sufficient strain, Ge becomes direct-band gap, thus enabling facile interband light emission and the fabrication of Group IV lasers. It has, however, not been possible to impart sufficient strain to Ge to reach the direct-band gap goal, because bulk Ge fractures at much lower strains. Here it is shown that very thin sheets of Ge(001), called nanomembranes (NMs), can be used to overcome this materials limitation.

ISBN: 9781321526608Subjects--Topical Terms:

543314
Materials science.

Maximizing Tensile Strain in Germanium Nanomembranes for Enhanced Optoelectronic Properties.
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020 $a 9781321526608
035 $a (MiAaPQ)AAI3680587
035 $a AAI3680587
040 $a MiAaPQ $c MiAaPQ
100 1 $a Sanchez Perez, Jose Roberto. $3 3176886
245 1 0 $a Maximizing Tensile Strain in Germanium Nanomembranes for Enhanced Optoelectronic Properties.
300 $a 120 p.
500 $a Source: Dissertation Abstracts International, Volume: 76-06(E), Section: B.
500 $a Adviser: Max G. Lagally.
502 $a Thesis (Ph.D.)--The University of Wisconsin - Madison, 2015.
506 $a This item must not be sold to any third party vendors.
520 $a Silicon, germanium, and their alloys, which provide the leading materials platform of microelectronics, are extremely inefficient light emitters because of their indirect fundamental energy band gap. This basic materials property has so far hindered the development of group-IV photonic-active devices, including light emitters and diode lasers, thereby significantly limiting our ability to integrate electronic and photonic functionalities at the chip level. Theoretical studies have predicted that tensile strain in Ge lowers the direct energy band gap relative to the indirect one, and that, with sufficient strain, Ge becomes direct-band gap, thus enabling facile interband light emission and the fabrication of Group IV lasers. It has, however, not been possible to impart sufficient strain to Ge to reach the direct-band gap goal, because bulk Ge fractures at much lower strains. Here it is shown that very thin sheets of Ge(001), called nanomembranes (NMs), can be used to overcome this materials limitation.
520 $a Germanium nanomembranes (NMs) in the range of thicknesses from 20nm to 100nm were fabricated and then transferred and mounted to a flexible substrate [a polyimide (PI) sheet]. An apparatus was developed to stress the PI/NM combination and provide for in-situ Raman measurements of the strain as a function of applied stress. This arrangement allowed for the introduction of sufficient biaxial tensile strain (>1.7%) to transform Ge to a direct-band gap material, as determined by photoluminescence (PL) measurements and theory. Appropriate shifts in the emission spectrum and increases in PL intensities were observed.
520 $a The advance in this work was nanomembrane fabrication technology; i.e., making thin enough Ge sheets to accept sufficiently high levels of strain without fracture. It was of interest to determine if the strain at which fracture ultimately does occur can be raised, by evaluating factors that initiate fracture. Attempts to assess the effect of free edges (enchant access holes) on the NM were made and an increase of 35% in the strain to at which crack first formed was found on NMs that lack etchant access holes. Ge NMs were used as a platform to investigate the relationships between surface passivation / functionalization and the physical properties of the material.
590 $a School code: 0262.
650 4 $a Materials science. $3 543314
650 4 $a Nanoscience. $3 587832
690 $a 0794
690 $a 0565
710 2 $a The University of Wisconsin - Madison. $b Materials Science. $3 2106447
773 0 $t Dissertation Abstracts International $g 76-06B(E).
790 $a 0262
791 $a Ph.D.
792 $a 2015
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3680587