Epitaxial growth and semiconductor properties of NiGa2O4 spinel for Ga2O3/NiO interfaces

Fuente: arXiv
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Main Authors: Egbo, Kingsley, Garrity, Emily M., Gowda, Shivashree Shivamade, Zare, Saman, Scott, Ethan A., Teeter, Glenn, Tellekamp, Brooks, Stevanovic, Vladan, Hopkins, Patrick E., Zakutayev, Andriy, Haegel, Nancy
Format: Preprint
Published: 2025
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author Egbo, Kingsley
Garrity, Emily M.
Gowda, Shivashree Shivamade
Zare, Saman
Scott, Ethan A.
Teeter, Glenn
Tellekamp, Brooks
Stevanovic, Vladan
Hopkins, Patrick E.
Zakutayev, Andriy
Haegel, Nancy
author_facet Egbo, Kingsley
Garrity, Emily M.
Gowda, Shivashree Shivamade
Zare, Saman
Scott, Ethan A.
Teeter, Glenn
Tellekamp, Brooks
Stevanovic, Vladan
Hopkins, Patrick E.
Zakutayev, Andriy
Haegel, Nancy
contents Unintentionally formed interfacial layers are ubiquitous in semiconductor devices that operate at extreme conditions. However, these layers' structure and properties often remain unknown due to the thinness of these naturally formed interphases. Here, we report on the intentional epitaxial growth and semiconductor properties of NiGa2O4 spinel layers that form at Ga2O3/NiO interfaces used in high-power and high-temperature electronic devices. Cubic spinel NiGa2O4 films of 10-50 nm thicknesses and low surface roughness (~ 2 nm) were grown using pulsed laser deposition at a substrate temperatures in the 300-900 °C range on α-Al2O3 and β-Ga2O3 substrates of different orientation. The optical absorption onset (3.6-3.9 eV) and thermal conductivity (4-9 W m-1 K-1) vary systematically with substrate temperature, consistent with theoretical predictions of varying Ni and Ga cation ordering on the spinel lattice. The valence band offset between NiGa2O4 and β-Ga2O3 is determined to be 1.8 eV. The NiGa2O4-based p-n heterojunction devices on Ga2O3 (001) substrates exhibit a rectification ratio of 10^8 (for +/-2V) and a turn-on voltage of 1.4 V, maintaining diode behavior up to 600 °C. These results highlight the potential of NiGa2O4 as a p-type interlayer in Ga2O3-based devices and shows a new approach to investigate such interfacial layers.
format Preprint
id arxiv_https___arxiv_org_abs_2512_20841
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Epitaxial growth and semiconductor properties of NiGa2O4 spinel for Ga2O3/NiO interfaces
Egbo, Kingsley
Garrity, Emily M.
Gowda, Shivashree Shivamade
Zare, Saman
Scott, Ethan A.
Teeter, Glenn
Tellekamp, Brooks
Stevanovic, Vladan
Hopkins, Patrick E.
Zakutayev, Andriy
Haegel, Nancy
Materials Science
Unintentionally formed interfacial layers are ubiquitous in semiconductor devices that operate at extreme conditions. However, these layers' structure and properties often remain unknown due to the thinness of these naturally formed interphases. Here, we report on the intentional epitaxial growth and semiconductor properties of NiGa2O4 spinel layers that form at Ga2O3/NiO interfaces used in high-power and high-temperature electronic devices. Cubic spinel NiGa2O4 films of 10-50 nm thicknesses and low surface roughness (~ 2 nm) were grown using pulsed laser deposition at a substrate temperatures in the 300-900 °C range on α-Al2O3 and β-Ga2O3 substrates of different orientation. The optical absorption onset (3.6-3.9 eV) and thermal conductivity (4-9 W m-1 K-1) vary systematically with substrate temperature, consistent with theoretical predictions of varying Ni and Ga cation ordering on the spinel lattice. The valence band offset between NiGa2O4 and β-Ga2O3 is determined to be 1.8 eV. The NiGa2O4-based p-n heterojunction devices on Ga2O3 (001) substrates exhibit a rectification ratio of 10^8 (for +/-2V) and a turn-on voltage of 1.4 V, maintaining diode behavior up to 600 °C. These results highlight the potential of NiGa2O4 as a p-type interlayer in Ga2O3-based devices and shows a new approach to investigate such interfacial layers.
title Epitaxial growth and semiconductor properties of NiGa2O4 spinel for Ga2O3/NiO interfaces
topic Materials Science
url https://arxiv.org/abs/2512.20841