Title: Nitrogen stabilizes the wurtzite polymorph in ZnSe _{1− x} Te _x thin films

Abstract

Materials based on tetrahedral structural motifs are the most used semiconductor systems in deployed technologies. This holds true for microelectronics based on doped Si (diamond structure), photovoltaics based on CdTe (zinc blende structure), and light emitting diodes based on GaN (wurtzite structure). In these compound examples, the extended crystal structure is determined by modifications to the arrangement of the underlying tetrahedral motifs; controlling this structure is a foundational way to design functionality in semiconductor materials. Here, N-doped ZnSe_1-xTe_x thin films are grown by RF sputtering from compound targets with N₂ gas as a N source. Crystalline films form across a large range of growth conditions, and in some N-doped films there is a transformation from the usual zinc blende structure to wurtzite. Depending on the temperature and N₂ flow rate during growth, wurtzite can be synthesized across most of the composition range explored, ranging from Te-rich (x ≈ 0.7) to nearly pure ZnSe (x ≈ 0.1). Synchrotron diffraction data show that the wurtzite is phase-pure at N-doped ZnSe_0.5Te_0.5 alloy compositions grown under some conditions. Temperature-dependent resistivity measurements collected from N-doped ZnSe_0.5Te_0.5 are well fit by a model dominated by variable range hopping, suggesting defect-mediated transport. Density functional theory calculations thatmore » show that dilute N concentrations help stabilize the wurtzite polymorph of ZnSe_0.5Te_0.5. Electron microscopy reveals voids in the N-doped films’ microstructures. We attribute this more open microstructure—which may also be partially responsible for stabilizing the wurtzite phase—to trapped N₂. This work highlights unexpected polytypism in one of the most studied semiconductor systems, motivating a closer look at other semiconductor alloys for similar structural diversity.« less

Authors:

Culman, Theodore H.  ^[1];

• Search DOE PAGES for author "Culman, Theodore H."
• Search DOE PAGES for ORCID "0000-0002-6456-1312"

Woods-Robinson, Rachel  ^[2];

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• Search DOE PAGES for ORCID "0000-0001-5009-9510"

Mangum, John S.  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-5926-7565"

Smaha, Rebecca W.  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-8349-2615"

Rom, Christopher L.  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-6176-3197"

Zakutayev, Andriy  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-3054-5525"

Bauers, Sage R.  ^[1]

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• Search DOE PAGES for ORCID "0000-0002-6505-5016"

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+ Show Author Affiliations

1. National Renewable Energy Laboratory, Golden, CO, USA
2. Lawrence Berkeley National Laboratory, Berkeley, CA, USA

Publication Date:

Thu Nov 03 00:00:00 EDT 2022

Research Org.:

National Renewable Energy Laboratory (NREL), Golden, CO (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Workforce Development for Teachers and Scientists (WDTS); USDOE Laboratory Directed Research and Development (LDRD) Program

OSTI Identifier:

1891938

Alternate Identifier(s):

OSTI ID: 1898370

Report Number(s):

NREL/JA-5K00-83292
Journal ID: ISSN 2050-7526; JMCCCX

Grant/Contract Number:  

AC36-08GO28308; SC0021266

Resource Type:

Published Article

Journal Name:

Journal of Materials Chemistry C

Additional Journal Information:

Journal Name: Journal of Materials Chemistry C Journal Volume: 10 Journal Issue: 42; Journal ID: ISSN 2050-7526

Publisher:

Royal Society of Chemistry (RSC)

Country of Publication:

United Kingdom

Language:

English

Subject:

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 36 MATERIALS SCIENCE; chalcogenide; materials discovery; photoabsorber; semiconductor