This readme file was generated on 2026-10-05 by Marc Thelen

# GENERAL INFORMATION

* Title of Dataset: Research data for: Shaping the electric field: Overcoming geometric inhomogeneities in the electrochemical fabrication of mesoporous materials

## Author/Principal Investigator Information
* Name: Marc Thelen
* ORCID: 0000-0002-4931-4436
* Institution: Institute for Materials and X-Ray Physics, Hamburg University of Technology; Centre for X-Ray and Nano Science CXNS, Deutsches Elektronen-Synchrotron DESY
* Address: Hamburg University of Technology, 21073 Hamburg, Germany
* Email: marc.thelen@tuhh.de

## Author/Associate or Co-investigator Information
* Name: Manuel Brinker
* ORCID: 0000-0002-1729-459X
* Institution: Institute for Materials and X-Ray Physics, Hamburg University of Technology; Centre for X-Ray and Nano Science CXNS, Deutsches Elektronen-Synchrotron DESY
* Address: Hamburg University of Technology, 21073 Hamburg, Germany
* Email: manuel.brinker@tuhh.de

## Author/Alternative Contact Information
* Name: Patrick Huber
* ORCID: 0000-0002-2126-9100
* Institution: Institute for Materials and X-Ray Physics, Hamburg University of Technology; Centre for X-Ray and Nano Science CXNS, Deutsches Elektronen-Synchrotron DESY
* Address: Hamburg University of Technology, 21073 Hamburg, Germany
* Email: patrick.huber@tuhh.de

# SHARING/ACCESS INFORMATION

* Licenses/restrictions placed on the data: CC BY 4.0
* Links to publications that cite or use the data: M. Thelen, M. Brinker, P. Huber, ACS Appl. Eng. Mater. 2026, https://doi.org/10.1021/acsaenm.6c01020
* Links to other publicly accessible locations of the data: none
* Links/relationships to ancillary data sets: none
* Was data derived from another source? No
* Recommended citation for this dataset: Thelen, M.; Brinker, M.; Huber, P. Research data for: Shaping the electric field: Overcoming geometric inhomogeneities in the electrochemical fabrication of mesoporous materials. TORE, 2026. https://doi.org/10.15480/882.18502


# DATA & FILE OVERVIEW

The study compares three electrochemical etching cells (A, B, C) that differ in the height of the internal widening step (4.75, 8.00 and 25.0 mm). One mesoporous silicon sample was etched in each cell.

| Cell | NIR sample ID | COMSOL model ID |
|---|---|---|
| A | 1851251014 | V2 |
| B | 1841251008 | V0 |
| C | 1831251008 | V5p3 |

## File List

NIR reflectance measurements:
* `<sampleID>_pSi_<YYMMDD>_(<n>)_areascan_cleaned.h5` / `_2xcleaned.h5`: area scan of the sample in ambient air
* `<sampleID>_pSi_<YYMMDD>_(<n>)_areascan_EtOH.h5`: area scan of the same sample infiltrated with ethanol
* `*_scan1.html`: interactive preview of each area scan (opens in a web browser)
* `1741250707_pSi_(1)_reference&dark.h5`: dark spectrum used for the dark correction of all area scans (the bulk-silicon reference spectrum in this file was not used, see Methods for processing the data)
* `1741250707_pSi_(1)_reference&dark_reference.png`, `..._dark.png`: plots of these spectra

COMSOL simulations:
* `hyperelastic_seal_cell<modelID>_260617.mph`: solid mechanics models of the compressed O-ring. The resulting seal shape is used in the current distribution models.
* `fielddistribution_<modelID>_260612.mph`: current distribution models of each cell. `V5p3` also contains the parametric sweeps (step height, seal overlap, obstacle).

## Details
* Relationship between files: the air and ethanol scans of one sample are evaluated together to separate layer thickness and porosity.
* Additional related data collected that was not included in the current data package: none
* Are there multiple versions of the dataset? No
* Date of data collection: NIR measurements 2025-07-07 (dark spectrum) and 2025-11-02 to 2025-11-03 (area scans); simulations 2026-06
* Geographic location of data collection: Hamburg, Germany
* Information about funding sources that supported the collection of the data: Deutsche Forschungsgemeinschaft (DFG) through the Excellence Strategy, EXC 3120/1 BlueMat: Water-Driven Materials (533771286); ANR-DFG project HySiSound (529978790); CRC 1615 SMART REACTORS (503850735)

# METHODOLOGICAL INFORMATION

## Description of methods used for collection/generation of data
See the Materials and Methods section of the publication (https://doi.org/10.1021/acsaenm.6c01020). Each sample was scanned over 40 mm × 40 mm at 0.35 mm pitch, once in air and once in ethanol. The simulations are 2D axisymmetric primary current distribution models in COMSOL Multiphysics.

## Methods for processing the data
The HDF5 files contain raw spectra. In the publication, only the NIR spectrometer (2101075U1) was evaluated. All spectra were divided by their integration time and normalised as R = (S − D) / (S_ref − D), with S the spectrum at a scan point, D the dark spectrum from `1741250707_pSi_(1)_reference&dark.h5` and S_ref the spectrum at a point on unetched bulk silicon outside the etched area of the same scan (stage position x, y = 34, 34 mm for sample A; 66, 66 mm for B; 34, 66 mm for C; same position in the air and ethanol scan). The normalised spectra were restricted to 1150–1350 nm and Fourier transformed to obtain the effective optical thickness. Only points within the etched area were evaluated.

## Instrument- or software-specific information needed to interpret the data
* Spectrometers: Avantes AvaSpec, serial 2101075U1 (NIR, 512 px, 894–1692 nm, used in the publication) and 2012190U1 (UV/VIS, 2048 px, 176–1334 nm), recording simultaneously
* HDF5 files: readable with any HDF5 library (e.g. Python h5py, MATLAB h5read) or HDFView
* COMSOL Multiphysics 6.4 (`fielddistribution_*`) with Corrosion Module and CAD Import Module; COMSOL Multiphysics 6.2 (`hyperelastic_seal_*`) with Structural Mechanics Module and Nonlinear Structural Materials Module
* Environmental/experimental conditions: room conditions
* People involved with sample collection, processing, analysis and/or submission: Marc Thelen, Manuel Brinker


# DATA-SPECIFIC INFORMATION FOR: *_areascan_*.h5

One group per spectrometer, named by serial number: `/2101075U1/scan_1/` (NIR) and `/2012190U1/scan_1/` (UV/VIS).

* Number of cases: 13 225 points per scan (115 × 115 grid)
* Variable List (N = 13 225 points, P = 512 or 2048 pixels):
	* `spectrum` (N × P): raw detector signal [counts]
	* `wavelength` (P): wavelength [m]
	* `position_x`, `position_y` (N): measured stage position [mm]
	* `position_x_target`, `position_y_target` (N): set stage position [mm]
	* `timestamp` (N): acquisition time [s, Unix time]
	* `timestamp_raw` (N): internal spectrometer counter
	* `saturated` (N × P): detector saturation per pixel [true/false]
	* Acquisition settings (e.g. `integration_time` [s], `num_averages`) are stored as attributes of `scan_1`.
* Missing data codes: none


# DATA-SPECIFIC INFORMATION FOR: 1741250707_pSi_(1)_reference&dark.h5

Groups `/spectrometer/NIR/scan_1/` and `/spectrometer/UVVIS/scan_1/`, each containing:
* `reference` (1 × P): spectrum of bulk silicon [counts] (not used in the publication)
* `dark` (1 × P): dark spectrum [counts] (used for the dark correction)
* `wavelengths` (P): wavelength [m]
* Acquisition settings are stored as attributes of each dataset. The integration time differs from that of the area scans (NIR: 0.0002 s vs. 0.001 s).
* Missing data codes: none