One more step unlocked to verify Cubic Boron Arsenide as the...

One more step unlocked to verify Cubic Boron Arsenide as the next-generation semiconductor by University of California - Santa Barbara.

With scanning ultrafast electron microscopy, researchers unveil hot photocarrier transport properties of cubic boron
OCTOBER 24, 2022
https://phys.org/news/2022-10-scanning-ultrafast-electron-microscopy-unveil.html

In a study that confirms its promise as the next-generation semiconductor material, UC Santa Barbara researchers have directly visualized the photocarrier transport properties of cubic boron arsenide single crystals.

"We were able to visualize how the charge moves in our sample," said Bolin Liao, an assistant professor of mechanical engineering in the College of Engineering.

Using the only scanning ultrafast electron microscopy (SUEM) setup in operation at a U.S. university, he and his team were able to make "movies" of the generation and transport processes of a photoexcited charge in this relatively little-studied III-V semiconductor material, which has recently been recognized as having extraordinary electrical and thermal properties.

In the process, they found another beneficial property that adds to the material's potential as the next great semiconductor.

• Boron arsenide is being eyed as a potential candidate to replace silicon, the computer world's staple semiconductor material, due to its promising performance.
• For one thing, with an improved charge mobility over silicon, it easily conducts current (electrons and their positively charged counterpart, "holes"). However, unlike silicon, it also conducts heat with ease.
• "This material actually has 10 times higher thermal conductivity than silicon," Liao said. This heat conducting—and releasing—ability is particularly important as electronic components become smaller and more densely packed, and pooled heat threatens the devices' performance, he explained.
• What gives rise to the high thermal conductivity of this material, it turns out, can also lead to interesting transport properties of photocarriers, which are the charges excited by light, for example, in a solar cell.
• If experimentally verified, this would indicate that cubic boron arsenide can also be a promising material for photovoltaic and light detection applications.
• Direct measurement of photocarrier transport in cubic boron arsenide, however, has been challenging due to the small size of available high-quality samples.
• When it comes to harvesting the energy from a typical solar cell, only the low-energy electrons are efficiently being collected; the high-energy ones tend to lose their energy rapidly as heat. Because of the persistence of the high-energy carriers in cubic boron arsenide, if this material was used as a solar cell, more energy could efficiently be harvested from it.
• With boron arsenide beating silicon in three relevant areas—charge mobility, thermal conductivity and hot photocarrier transport time—it has the potential to become the electronics world's next state-of-the-art material.