Title: Fabrication of stable, wide-bandgap thin films of Mg, Zn and O

Abstract

A stable, wide-bandgap (approximately 6 eV) ZnO/MgO multilayer thin film is fabricated using pulsed-laser deposition on c-plane Al₂O₃ substrates. Layers of ZnO alternate with layers of MgO. The thickness of MgO is a constant of approximately 1 nm; the thicknesses of ZnO layers vary from approximately 0.75 to 2.5 nm. Abrupt structural transitions from hexagonal to cubic phase follow a decrease in the thickness of ZnO sublayers within this range. The band gap of the thin films is also influenced by the crystalline structure of multilayer stacks. Thin films with hexagonal and cubic structure have band-gap values of 3.5 and 6 eV, respectively. In the hexagonal phase, Mg content of the films is approximately 40%; in the cubic phase Mg content is approximately 60%. The thin films are stable and their structural and optical properties are unaffected by annealing at 750.degree. C.

Inventors:

Katiyar, Ram S.; Bhattacharya, Pijush; Das, Rasmi R.

Issue Date:

2006-07-25

Research Org.:

University Of Puerto Rico, San Juan (Puerto Rico)

Sponsoring Org.:

USDOE

OSTI Identifier:

1175845

Patent Number(s):

7081371

Application Number:

10/932,656

Assignee:

University Of Puerto Rico (San Juan, PR)

Patent Classifications (CPCs):

C - CHEMISTRY C30 - CRYSTAL GROWTH C30B - SINGLE-CRYSTAL-GROWTH

H - ELECTRICITY H01 - BASIC ELECTRIC ELEMENTS H01L - SEMICONDUCTOR DEVICES

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C - CHEMISTRY C30 - CRYSTAL GROWTH C30B - SINGLE-CRYSTAL-GROWTH

C30B23/02 - Epitaxial-layer growth
C30B29/22 - Complex oxides
C30B29/52 - Alloys

H - ELECTRICITY H01 - BASIC ELECTRIC ELEMENTS H01L - SEMICONDUCTOR DEVICES

H01L21/0242 - {Crystalline insulating materials}
H01L21/02472 - {Oxides}
H01L21/02488 - {Insulating materials}
H01L21/02507 - {Alternating layers, e.g. superlattice}
H01L21/02554 - {Oxides}
H01L21/02565 - {Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds}
H01L21/02631 - {Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation}
H01L21/02661 - {In-situ cleaning}

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DOE Contract Number:  

F6-02*01ER45868

Resource Type:

Patent

Resource Relation:

Patent File Date: 2004 Sep 02

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE