Platform for Graphene Sensors Using Printed Circuit Boards and Single Board Computers
Bibliographic record
Abstract
A platform was designed to allow electrical measurements to be taken from graphene sensors without the need for a probing bench or other lab equipment.Research began with the characterization of a range of different sensors, including various types of graphene field-effect transistors (GFET), interdigitated electrodes (IDE), and Hall sensors.Out of all the dropcast FETs that were tested, 23.6% were within a 20% margin of the expected resistance.Testing for Hall sensors involved measuring resistivity and hall coefficient on a set of two bars that were perpendicular to the direction of the current.9 out of the 64 hall sensors tested had resistivity and hall coefficients that were within 10% of each other on each bar.A selection of sensors, namely the hall, dropcast GFET (or "droplet"), and infrared sensors then had circuit boards designed to house them.The PCBs were designed to be connected to the GPIO of a Raspberry Pi, which could then supply voltage and read measurements using a MATLAB script.The hall and droplet sensors had two variants designed for them, one with fewer components to be used in conjunction with an ADC expansion board for the Raspberry Pi, and a more complex board with an on-board ADC.ADC variants for the boards were simulated in LTspice, while testing of the platform was done with a Graphenea S20 GFET chip mounted on one of the IR boards and included a breadboard and resistor to create a voltage divider.After initial calibration, resistance measurements from the Raspberry pi were accurate within 1% to those taken with a semiconductor parameter analyzer.iii A method was developed to successfully refresh the graphene with acetone without damaging the PCB, raising the resistance of the GFETs by 701Ω on average.Results from using wax encapsulation to slow or stop resistance drift are inconclusive, the chip with wax had average resistance that shifted -40.1Ω to +25.5Ω per day, while the resistance drift on the chip without wax was -75.4Ω to +52.2Ω per day.knowledge, finances, or labor.First and foremost I would like to thank my supervisor, Rony Amaya, for the guidance and support that I have
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.023 | 0.009 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".