In-Substrate Imaging of Diamond hBN FET Current via Widefield Quantum Diamond Microscopy

• URL: http://arxiv.org/abs/2601.15355v1
• Date: Wed, 21 Jan 2026 06:57:57 GMT
• Title: In-Substrate Imaging of Diamond hBN FET Current via Widefield Quantum Diamond Microscopy
• Authors: Anuj Bathla, Subrat Kumar Pradhan, Ajit Kumar Dash, Prabhat Anand, M. Girish Chandra, Kenji Watanabe, Takashi Taniguchi, Akshay Singh, Veeresh Deshpande, Kasturi Saha,
• Abstract summary: Hydrogen termination of the diamond surface induces a two dimensional hole gas (2DHG)<n>An ensemble of near surface NV centers located $ sim 1m$ below the surface enables noninvasive magnetic imaging of current flow with micrometer scale spatial resolution.<n>Magnetic field maps and reconstructed current density distributions visualize directly current injection at the source drain contacts and transport beneath the hBN gated channel.
• Score: 2.4776734774603724
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: We demonstrate widefield magnetic imaging of current flow in hydrogen terminated diamond field effect transistors (FETs) through in-substrate nitrogen vacancy (NV) centers. Hydrogen termination of the diamond surface induces a two dimensional hole gas (2DHG), while an ensemble of near surface NV centers located $ \sim 1~μm$ below the surface enables noninvasive magnetic imaging of current flow with micrometer scale spatial resolution. The FETs were electrically characterized over a range of drain source biases $V_{ds}= 0$ to $-15V$ and gate voltages,$V_{gs}= +3$ to $-9V$ followed by in situ widefield NV magnetometry during device operation. Magnetic field maps and reconstructed current density distributions directly visualize current injection at the source drain contacts and transport beneath the hBN gated channel. Magnetic field maps reveal current density variations in the channel region owing to non-uniformities or defects in the gate dielectric. In addition, we observe a pronounced enhancement of the drain current ($\sim 600-900 μA$) and a shift in the apparent threshold voltage during laser illumination, reflecting photo induced changes in channel electrostatics. By correlating gate dependent magnetic images with simultaneous electrical measurements, we directly link spatial current distributions to FET transfer characteristics, providing new insight into buried interface transport and non-uniform gating effects in the transistor channel. As the methodology is compatible with top gated FETs, it can be used to map channel current distributions with micrometer resolution in emerging channel materials, such as 2D materials and wide bandgap channels, and establish widefield NV magnetometry as a powerful platform for probing charge transport in transistors and Van der Waals dielectric heterostructures.

Related papers

• Streamline controlled rectification of supercurrent in thin-film asymmetric weak links [39.58317527488534]
  We study the supercurrent diode effect (SDE) in mesoscopic superconducting weak links formed by asymmetric Dayem bridges.<n>By implementing controlled geometric defects at the junction between the constriction and superconducting leads, we induce current crowding and disrupt spatial symmetry.<n>Our findings advocate for mesoscopic Dayem bridges as a flexible platform for designing and controlling superconducting diode functionalities.
  arXiv  Detail & Related papers  (2025-07-16T14:26:18Z)
• Sensing Electric Currents in an a-IGZO TFT-Based Circuit Using a Quantum Diamond Microscope [0.0]
  The Quantum Diamond Microscope (QDM) is an emerging magnetic imaging tool enabling characterization of electronic circuits.<n>We demonstrate wafer-level current sensing of a current mirror circuit composed of 16 amorphous-indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs)<n>Our results highlight QDM's capability as a noninvasive diagnostic tool for the characterization of emerging semiconductor technologies.
  arXiv  Detail & Related papers  (2025-06-21T15:38:58Z)
• Imaging current flow and injection in scalable graphene devices through NV-magnetometry [0.0]
  We use high-resolution nitrogen-vacancy (NV) magnetometry to visualise the charge flow in gold-contacted, single-layer graphene devices.<n>Our findings establish high-resolution NV-magnetometry as a key tool for characterizing scalable 2D material based devices.
  arXiv  Detail & Related papers  (2025-02-16T10:52:48Z)
• Investigation of the Effects of the Multiplication Area Shape on the Operational Parameters of InGaAs/InAlAs SPADs [75.38606213726906]
  Changing the diameter of the structure's active region leads to a change in the dark current in the linear part of the current-voltage curve. It is reasonable to pick specific SPADs from a batch on the sole basis of their current-voltage curves.
  arXiv  Detail & Related papers  (2023-10-06T10:38:14Z)
• Multilevel resonant tunneling in the presence of flux and charge noise [64.0476282000118]
  Macroscopic resonant tunneling (MRT) in flux qubits is an important experimental tool for extracting information about noise produced by a qubit's surroundings. We present a detailed derivation of the MRT signal in the RF-SQUID flux qubit allowing for effects of flux and charge fluctuations on the interwell and intrawell transitions in the system.
  arXiv  Detail & Related papers  (2022-09-21T18:59:36Z)
• Current Paths in an Atomic Precision Advanced Manufactured Device Imaged by Nitrogen-Vacancy Diamond Magnetic Microscopy [0.0]
  Nitrogen-vacancy (NV) wide-field magnetic imaging of stray magnetic fields from surface current densities flowing in an APAM test device over a mm-field of view with mum-resolution. Analysis on the current density reconstructed map showed a projected sensitivity of 0.03 A/m, corresponding to a smallest detectable current in the 200 mum-wide APAM ribbon of 6 muA. These results demonstrate the failure analysis capability of NV wide-field magnetometry for APAM materials, opening the possibility to investigate other cutting-edge microelectronic devices.
  arXiv  Detail & Related papers  (2022-07-28T17:38:51Z)
• Vector Magnetic Current Imaging of an 8 nm Process Node Chip and 3D Current Distributions Using the Quantum Diamond Microscope [1.2233362977312945]
  We present the measurement of 2D current distributions in an 8-nm flip chip IC and 3D current distributions in a multi-layer PCB. Magnetic field emanations from the C4 bumps in the flip chip dominate the QDM measurements. We show how magnetic field images of individual layers can be subtracted from the magnetic field image of the total structure.
  arXiv  Detail & Related papers  (2022-02-16T15:23:30Z)
• Imaging of sub-$\mu$A currents in bilayer graphene using a scanning diamond magnetometer [0.0]
  We report on sensitive magnetic imaging of two-dimensional current distributions in bilayer graphene at room temperature. Current density maps reveal local variations in the flow pattern and global tuning of current flow via the back-gate potential. Our experiments demonstrate the feasibility for imaging subtle features of nanoscale transport in two-dimensional materials and conductors.
  arXiv  Detail & Related papers  (2022-01-18T12:53:46Z)
• TOF-SIMS Analysis of Decoherence Sources in Nb Superconducting Resonators [48.7576911714538]
  Superconducting qubits have emerged as a potentially foundational platform technology. Material quality and interfacial structures continue to curb device performance. Two-level system defects in the thin film and adjacent regions introduce noise and dissipate electromagnetic energy.
  arXiv  Detail & Related papers  (2021-08-30T22:22:47Z)
• High speed microcircuit and synthetic biosignal widefield imaging using nitrogen vacancies in diamond [44.62475518267084]
  We show how to image signals from a microscopic lithographically patterned circuit at the micrometer scale. Using a new type of lock-in amplifier camera, we demonstrate sub-millisecond spatially resolved recovery of AC and pulsed electrical current signals. Finally, we demonstrate as a proof of principle the recovery of synthetic signals replicating the exact form of signals in a biological neural network.
  arXiv  Detail & Related papers  (2021-07-29T16:27:39Z)
• Continuous-Wave Frequency Upconversion with a Molecular Optomechanical Nanocavity [46.43254474406406]
  We use molecular cavity optomechanics to demonstrate upconversion of sub-microwatt continuous-wave signals at $sim$32THz into the visible domain at ambient conditions. The device consists in a plasmonic nanocavity hosting a small number of molecules. The incoming field resonantly drives a collective molecular vibration, which imprints an optomechanical modulation on a visible pump laser.
  arXiv  Detail & Related papers  (2021-07-07T06:23:14Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.