RT Measurements¶
RT (Room Temperature) measurements encompass various electrical and optical characterization techniques performed at ambient conditions. These provide quick, non-destructive assessment of material properties.
Overview¶
This schema package defines:
- RTMeasurement - Room temperature electrical and optical measurements with flexible parameter documentation
RT measurements extend BaseMeasurement, providing:
- Links to measured samples and instrument
- Flexible parameter definitions for various measurement types
- Electrical properties (resistance, conductivity, carrier concentration)
- Optical properties (transmission, reflection, absorption)
- Quick screening data
Typical Usage¶
- Select samples: Reference samples to characterize
- Choose measurement type: Electrical (I-V, Hall, 4-point probe) or optical (transmission, reflection)
- Configure setup: Probe configuration, voltage/current ranges, light sources
- Record data: Measurement results and conditions
- Extract properties: Calculate conductivity, mobility, bandgap, etc.
Common RT Measurement Types¶
Electrical Measurements¶
- Four-point probe: Sheet resistance, conductivity
- Hall effect: Carrier concentration, mobility, type (n or p)
- I-V curves: Diode characteristics, contact resistance
- Capacitance-voltage: Depletion width, doping profiles
Optical Measurements¶
- Transmission: Optical transparency, absorption edge
- Reflection: Surface reflectivity, optical constants
- Absorption: Calculated from transmission and reflection
- Quick PL: Simple emission screening (detailed PL in PL measurements)
What RT Measurements Tell You¶
- Electrical conductivity: Is the material conductive?
- Carrier type: n-type or p-type semiconductor
- Carrier concentration: Doping level or defect density
- Mobility: Charge transport quality
- Optical bandgap: From absorption edge (Tauc plot)
- Transparency: For transparent conductor applications
RT Screening for Combinatorial Libraries¶
- Quick assessment: Fast measurements across composition space
- Identify trends: Composition-property relationships
- Guide selection: Choose promising samples for detailed characterization
- Pre-screening: Before time-consuming measurements like XRD, XPS
Key Parameters¶
- Probe configuration: Two-point, four-point, Hall bar geometry
- Current/voltage: Applied bias, current range
- Magnetic field: For Hall measurements
- Light source: Wavelength, intensity for optical measurements
- Environment: Air, vacuum, controlled atmosphere
Related Schemas¶
- Measured samples: Samples from Sputtering, RTP
- Instrument: DTUInstrument (probe stations, optical setups)
- Detailed optical: PL, Ellipsometry for advanced characterization
- Analysis: Jupyter Analysis for property extraction, Tauc plots
Schema Documentation¶
RTSpectrum¶
description: Single R or T spectrum with measurement geometry information.
inherits from: nomad.datamodel.data.ArchiveSection
properties:
| name | type | |
|---|---|---|
| spectrum_type | ['Reflection', 'Transmission'] |
Type of spectrum: Reflection (R) or Transmission (T). |
| wavelength | float64 |
Wavelength array in nanometers. shape= ['*'], unit=nanometer |
| intensity | float64 |
Intensity values (R or T as fraction 0-1). shape= ['*'] |
| detector_angle | float64 |
Detector angle in degrees, the angle between the beam and the detector. 180° means is in the direction of the transmitted beam (typically for transmission measurements), while small angles means it is in the direction of the reflected beam (typically for reflection measurements). Angles constrained between 12 and 180° (if the beam is detector is on the left side of the optical path) and -12 and -179° (if the detector is on the right side of the optical path) based on typical Agilent Cary 7000 UMS configurations. unit= degree |
| sample_angle | float64 |
Sample angle in degrees, the angle between the beam and the sample surface. 0° means the beam is normal to the sample surface, while larger angles mean the beam is more grazing. Angles are typically between 0 and 85° based on typical Agilent Cary 7000 UMS configurations. unit= degree |
| polarization | ['p', 's', 'unpolarized(p-biased)'] |
Polarisation of the light if the polarizer element was used during the measurement. 's (angle 0°)' means the electric field is perpendicular to the plane of incidence, 'p (angle 90°)' means the electric field is parallel to the plane of incidence, and 'unpolarized (p-biased)' means the polarizer was set to unpolarized mode to increase measurement throughput, which typically results in a p-polarized bias in the transmitted beam. |
normalization:
The normalizer for the RTSpectrum class.
RTResult¶
description: Results from a single spatial position containing multiple R/T spectra.
inherits from: nomad_measurements.mapping.schema.MappingResult
properties:
| name | type | |
|---|---|---|
| spectra | RTSpectrum |
List of Reflection and/or Transmission spectra measured at this position. sub-section, repeats |
normalization:
Normalizes the results data for the RT measurement.
DTUSampleAlignment¶
description: The alignment of the sample on the stage.
inherits from: nomad_measurements.mapping.schema.RectangularSampleAlignment
normalization:
The normalizer for the RectangularSampleAlignment class.
Will calculate the affine transformation from the sample alignment.
Args: archive (EntryArchive): The archive containing the section that is being normalized. logger (BoundLogger): A structlog logger.
DtuAutosamplerMeasurement¶
description: Experiment container for autosampler R/T measurements
inherits from: nomad.datamodel.metainfo.basesections.v1.Experiment, nomad.datamodel.data.EntryData
properties:
| name | type | |
|---|---|---|
| data_file | str |
CSV file containing all R and T spectra recorded by the Agilent Cary 7000 UMS autosampler. This file contains the raw spectral data along with metadata and needs to be parsed together with the config file to extract individual spectra and associate them with the correct sample/library and position. |
| config_file | str |
CSV file containing the grid/position metadata mapping. This file maps each position on each library to the corresponding recorded spectra in the data file, (Ex: the first recorded spectrum of the data_file has been recorded at position X=5mm, Y=10mm on library "eugbe_0025_Zr_FL") |
| raw_file | str |
Raw binary file from the Agilent Cary 7000 UMS instrument (for bookkeeping and data provenance). File extension is typically .bsw. |
normalization:
The normalizer for the DtuAutosamplerMeasurement class.
This method: 1. Parses the data and config files using autosampler_reader 2. Groups data by sample/library 3. Creates separate RTMeasurement archives for each library 4. Adds them as steps to this experiment
RTMeasurement¶
inherits from: nomad_dtu_nanolab_plugin.schema_packages.basesections.DtuNanolabMeasurement, nomad.datamodel.metainfo.plot.PlotSection, nomad.datamodel.data.EntryData
properties:
| name | type | |
|---|---|---|
| results | RTResult |
The result of the measurement. sub-section, repeats |
| sample_alignment | DTUSampleAlignment |
The alignment of the sample. sub-section |
normalization:
The normalizer for the RTMeasurement class.