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14 parameters at once: a new device for optoelectronics

Bright circles represent charge carriers (negative and positive) bound in the material. The light beam separates these charges, which are then deflected in various ways by the applied magnetic field. With the CLIMAT method, about 14 different parameters of transport properties in semiconductors can be measured with a single measurement, for example, density, lifetime, diffusion length, and mobility. Credit: Laura Canil (www.canilvisuals.com) via Helmholtz Association of German Research Centers

A HZB physicist has developed a new method for comprehensive characterization of semiconductors in a single measurement. “Constant Light-Induced Magneto-Transport (CLIMAT)” is based on the Hall effect and allows the recording of 14 different parameters of the transport properties of negative and positive charge carriers.

The method has now been tested on twelve different semiconductor materials and will save valuable time in evaluating new materials for optoelectronic applications such as solar cells.

Solar cells, transistors, detectors, sensors, and LEDs all have one thing in common: they are made of semiconductor materials that have are only released when they collide with light (photons). Photons knock electrons (negative charge carriers) out of their orbits, which move through the material until they are recaptured after a certain time.

At the same time, holes are created at sites where electrons are missing—these holes behave like positively charged charge carriers and are critical to the performance of the respective application. The behavior of negative and positive charge carriers in semiconductors often differs by orders of magnitude in terms of mobility, diffusion length, and lifetime.

Until now, the parameters of the transport properties had to be determined separately for each type of charge, using different measurement methods.

Single measurement

As part of his Maria Sklodowska Curie postdoctoral fellowship, HZB physicist Dr. Artem Musyenko has now developed a new method that can record all 14 parameters of positive and negative charge carriers in a single measurement.

“Constant Light-Induced Magneto-Transport (CLIMAT)” uses a constant light source to induce a magnetic field and charge separation vertically through the sample. Charge carriers move together. And are deviating from According to their mass, mobility, and other properties perpendicular to their direction of motion (Hall effect).

A total of 14 different properties can be determined from the signals, and in particular the difference between the signals of different charge carriers, Musiienko showed with a small system of equations.

Positive and negative charge carriers

“CLIMAT thus provides a comprehensive insight into the complex mechanisms of charge transport, positive and negative charge carriers, with a single measurement. or for other applications,” says Mosyenko.

To demonstrate the broad applicability of the new method, research teams at HZB, Potsdam University, and other institutions in the US, Switzerland, UK, and Ukraine have now used it for a total of twelve properties. materials, including silicon, halide perovskite films, organic semiconductors such as Y6, semiconductors, self-assembled monolayers, and nanoparticles. Now the results are out. published I Nature Communications.

Independent experts such as Professor Vitaly Podzarov of Rutgers University, US, awarded Klimt’s method 15 out of 16 points. Nature Electronics And consider the new methodology groundbreaking.

In particular, CLIMAT eliminates many of the steps previously required for various measurements, thus saving valuable time. In early 2024, the CLIMAT method was granted a patent by the European Patent Office under the number EP23173681.0. “We are currently in discussions with companies about licensing our method,” Mosenko says. The goal is a compact measuring device about the size of a notebook.

More information:
Artem Musiienko et al, Resolving electron and hole transport properties in semiconductor materials by persistent light-induced magnetotransport, Nature Communications (2024). DOI: 10.1038/s41467-023-44418-1

Reference: 14 parameters at once: New instrument for optoelectronics (2024, February 21) Retrieved February 21, 2024, from https://phys.org/news/2024-02-parameters-instrument-optoelectronics.html

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