Researchers from IBM, the Korea Advanced Institute of Science and Technology, Korea Research Institute of Chemical Technology and Duke University have discovered a technique to get more information from semiconductors.
Edward Hall discovered Hall Voltage in 1879. Hall Voltage describes that electrical voltage occurs in the transverse direction of a current carrier when a magnetic field is applied perpendicular to the current and transverse direction.
Hall Voltage is important because it communicates information about the charge carriers, including the presence of negative electrons and positive quasi-particles called holes. It also provides information about the speed of these particles in an electric field.
The researchers have now found a technique to extract even more information from these load carriers, writes Venturebeat. These include the ages of the charge carriers, diffusion lengths and metrics about recombination. Recombination is the process by which electrons and so-called ‘holes’ destroy each other.
Scientists say that their technology can stimulate the progress of semiconductors in both existing and emerging technologies. “We now have the knowledge and tools needed to extract the physical characteristics of semiconductor materials in great detail,” say co-authors Oki Gunwan and Doug Bishop.
“For example, this will help accelerate development of next-generation semiconductor technology, such as better solar cells, better optoelectronics devices, and new materials and devices for artificial intelligence technology.”
The new approach – the so-called Carrier-Resolved Photo Hall (CRPH) measurement – begins with a known carrier density of the traditional Hall measurement in the dark. Light with a known illumination intensity is then introduced, allowing the wearer’s life span and the mobility and density of the majority and minority of the carrier to be detected.
With new measuring equipment – specifically a tool called parallel dipole line (PDL) trap – it should be easier to orchestrate. The PDL was developed four years ago by scientists from IBM, which later proved to be ideal for photo-Hall experiments. This is partly because of the space it offers to illuminate large areas on samples.
Clean Hall signal measurements are difficult to perform when the signal is weak or when there is unwanted noise, for example under lights. The measurements are best performed with systems such as the PDL, which provides an oscillating magnetic field. CRPH then selects the desired frequency of the target signal and the phase of the field.