SPCM · Optoelectronic mapping
A modular optoelectronic workstation for spatially resolved photoresponse, charge transport and optoelectronic heterogeneity.
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01 / Overview
Material characterization
The LST SPCM combines a compact confocal microscope head, closed-loop XYZ positioning and dedicated signal-recovery paths in a modular platform for advanced materials and optoelectronic devices. Unlike conventional stage-scanning systems, the microscope head moves while the specimen and its electrical connections remain stationary.
Closed-loop XYZ positioning with a stationary sample architecture
Photocurrent mapping for localized photoresponse measurements
Reflection mapping for spatial correlation and feature alignment
Integrated control and acquisition through purpose-built software
02 / Moving-head architecture
Keep connections referenced
Instead of translating the specimen during a scan, the LST SPCM moves the microscope head in three axes. This keeps contacted devices, probe needles, wiring and sample-environment hardware stationary while the optical measurement region is scanned.
Locate the region of interest using the widefield optical view.
Scan the microscope head over the selected region using closed-loop XYZ motion.
Acquire spatially registered reflection and photocurrent maps while the sample and electrical connections remain fixed.
03 / Measurement workflow
From navigation to response
The optical view identifies the device and region of interest. The reflection map registers spatial structure, while the photocurrent map reveals where the local electrical photoresponse is generated.
Find the device and define the region of interest.
Register optical contrast and spatial structure.
Locate and compare the electrical photoresponse.
04 / Scan control
Purpose-built motion tools
01 / Focus-plane control
Compensates for sample tilt or surface-height variation by adjusting the Z position during the scan, helping maintain focus across the selected measurement plane.
02 / Scan geometry
Defines scan regions in arbitrary orientations, allowing elongated or angled devices to be mapped efficiently without mechanically rotating the sample.
06 / Control software
Integrated acquisition
The cross-platform control suite brings scan setup, instrument synchronization, live reflection and photocurrent mapping, synchronized laser-power logging, line-profile analysis and data export into the measurement workflow.
07 / System architecture
Modular by design
The open-frame architecture is designed around configurable optomechanics and infinity-corrected optics, allowing key optical and sample-handling elements to be adapted for specific research requirements.
Configurable excitation and optical components
Camera-assisted sample navigation and alignment
Dedicated signal recovery and instrument synchronization
08 / Technical specifications
Standard SPCM configuration
The closed-loop XYZ platform scans the confocal microscope over a stationary specimen, allowing device contacts and compatible sample-environment hardware to remain in place during correlated optical and electrical mapping.
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Measurement performance: Sensitivity and acquisition time depend on the detector, preamplifier, lock-in configuration and bandwidth, modulation frequency, optical power, device impedance, grounding, shielding and environmental noise. Acquisition speed also depends on integration time and signal-to-noise requirements; total map time depends on settings and scan size. Final specifications are configuration- and application-dependent.
Technical documents
09 / Published research
SPCM publications
Spatially resolved optoelectronic measurements enabled by the LST SPCM platform.
Featured application · 2D Materials
Mohammadali Razeghi et al.
“Single-material MoS₂ thermoelectric junction enabled by substrate engineering”
npj 2D Materials and Applications, 2023, 7:36
In this study, scanning photocurrent microscopy was used to investigate thermoelectric junctions formed within few-layer MoS₂ by locally modifying the supporting substrate. Simultaneously acquired reflection and photocurrent maps revealed a bipolar photoresponse at the interfaces between supported and suspended regions of the crystal.
The publication explicitly identifies the measurement platform as a commercially available LST Scientific SPCM system. The experiment demonstrates the ability of the platform to spatially correlate optical structure with local electrical photoresponse in two-dimensional materials.
Reflection mapping + photocurrent mapping + electrical bias control
View PublicationSelected work
The LST SPCM platform builds on a research history in spatially resolved photocurrent microscopy. The publications below illustrate applications of SPCM investigated by researchers behind the development of the technology, spanning strongly correlated materials, metallic layered materials and two-dimensional semiconductors.
This foundational study forms part of the research history behind the development of LST’s SPCM technology. Scanning photocurrent microscopy was used to investigate the photoresponse of suspended VO₂ nanobeams across the metal–insulator transition.
Reflection and photocurrent measurements enabled spatially resolved investigation of metallic and insulating regions and their phase boundaries.
View PublicationPhysical Review B 97, 195412 (2018)
This work by researchers behind the LST SPCM technology demonstrates the use of scanning photocurrent microscopy to investigate photoresponse in metallic layered materials.
SPCM revealed contact-localized photocurrent at zero bias and a spatially distributed photoresponse under finite bias in 3R-NbS₂.
View Publication