Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 2407.02682

Epitaxial Growth of Rutile GeO$_2$ via MOCVD

Imteaz Rahaman·Bobby Duersch·Hunter D. Ellis·Michael A. Scarpulla·Kai Fu
View original source ↗Read source document ↗Export metadata ↓

Abstract

Rutile Germanium Dioxide (r-GeO$_2$) has been identified as an ultrawide bandgap (UWBG) semiconductor recently, featuring a bandgap of 4.68 eV, comparable to Ga$_2$O$_3$ but offering bipolar dopability, higher electron mobility, higher thermal conductivity, and higher Baliga's figure of merit (BFOM).These superior properties position GeO$_2$ as a promising material for various semiconductor applications. However, the epitaxial growth of r-GeO$_2$, particularly in its most advantageous rutile polymorph, is still at an early stage. This work explores the growth of r-GeO$_2$ using metal-organic chemical vapor deposition (MOCVD) on an r-TiO$_2$ (001) substrate, utilizing tetraethyl germane (TEGe) as the precursor. Our investigations reveal that higher growth temperatures significantly enhance crystalline quality, achieving a full width at half maximum (FWHM) of 0.181 degree at 925 degree C, compared to 0.54 degree at 840 degree C and amorphous structures at 725 degree C. Additionally, we found that longer growth durations increase surface roughness due to the formation of faceted crystals. Meanwhile, adjusting the susceptor rotation speed from 300 RPM to 170 RPM plays a crucial role in optimizing crystalline quality, effectively reducing surface roughness by approximately 15 times. This study offers a foundational guide for optimizing MOCVD growth conditions of r-GeO$_2$ films, emphasizing the crucial need for precise control over deposition temperature and rotation speed to enhance adatom mobility and effectively minimize the boundary layer thickness.

Explore related subjects

physics.app-phcond-mat.mtrl-sci

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Imteaz Rahaman, Bobby Duersch, Hunter D. Ellis, Michael A. Scarpulla, Kai Fu. 2024-07-02. Epitaxial Growth of Rutile GeO$_2$ via MOCVD. https://arxiv.org/abs/2407.02682

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Measuring vacancy-type defect density in monolayer semiconductors

Two-dimensional (2D) materials have attracted wide-spread interest due to their unique and tunable properties. Their optoelectronic, mechanical, and thermal properties are greatly influenced by crystal defects, which are, in turn, used to control these properties. However, experimental quantification of the density of defects, whether deliberately introduced or inherent, is very difficult in these atomically thin materials. Here we show that helium atom micro-diffraction can be used to measure the defect density in ~15x20um monolayer MoS2, a prototypical 2D semiconductor, quickly and easily compared to standard methods. We present a simple analytic model, the lattice gas equation, that captures the relationship between atomic Bragg diffraction intensity and defect density. The model, combined with ab initio scattering calculations, shows that our technique can immediately be applied to a wide range of 2D materials, independent of sample chemistry or structure. Additionally, wafer-scale characterization is immediately possible.

physics.app-ph↗
arXiv2026

Compact Modeling of Oxide-Semiconductor, 2D Material, Carbon Nanotube, and Cryogenic Transistors with Experiment Verification

This paper presents a unified compact model for emerging transistor technologies, including oxide-semiconductor field-effect transistors (OSFETs), 2D material FETs (2DFETs), carbon nanotube FETs (CNFETs), and cryogenic MOSFETs. A unified charge-density formulation is developed to account for quantum confinement, trap charges, and band-tail states in channel charge calculations. A physics-based transport model is introduced to seamlessly capture carrier transport from the long-channel diffusive regime to the short-channel ballistic limit. Scaling models are incorporated to accurately describe 2D electrostatic effects. Cryogenic operation is modeled through the inclusion of band-tail states and temperature-dependent mobility and threshold voltage. The proposed model is validated against experimental data from the fabricated OSFETs with multiple channel lengths and published measurements of 2DFETs, CNFETs, and cryogenic MOSFETs. Excellent agreement is demonstrated across diverse device architectures, operating conditions, and material systems.

physics.app-ph↗
arXiv2026

Multiplexing approaches to thermoradiative signatureless communications

Using mid-infrared emission from semiconductor devices for covert communications remains a relatively unexplored and yet promising opportunity. The phenomenon of negative luminescence allows for a method of signatureless covert communications where the net infrared emission of an emitting optoelectronic device is balanced to be identical to the ambient thermal background. In this work we provide a practical demonstration of covert data transfer over a thermoradiative channel with data rates up to 100 kbps. In addition, we demonstrate several additional multiplexing techniques that make the proposed thermoradiative communications method more secure against interception by achieving zero instantaneous optical emission, while remaining detectable if a sufficiently spatially or spectrally discerning observation is utilised. Finally, we discuss various application scenarios in which the proposed methods can be used to achieve secure signatureless communications.

physics.app-ph↗