The scientific research team overcomes the material problem, and germanium-tin alloy provides a new path for efficient LEDs

Silicon has long occupied a dominant position in the semiconductor material competition, but its "innate defects" in the field of optoelectronics also limit its growth space. Recently, researchers have developed a new semiconductor material composed of germanium and tin. Its light absorption and emission efficiency are better than silicon semiconductors, and it may become a new generation of high-performance semiconductors.

Silicon is the cornerstone of the modern electronics industry. The chips of most electronic products such as computers and mobile phones are mainly made of silicon, and it is still difficult to be replaced by other materials.

Although silicon has the advantages of mature technology and low cost, due to its "indirect bandgap" characteristics, the luminous efficiency is much lower than that of direct bandgap materials. It cannot be directly used as a high-efficiency laser or LED light source device, and it is difficult to show its talents in the field of optoelectronics.

In order to implement optical communications on a chip, engineers usually need to heterogeneously integrate expensive III-V materials, which is a complex and costly process. Therefore, scientists have long been committed to developing alternatives to Group IV materials, among which germanium-tin alloys are regarded as the "holy grail" in the semiconductor field.

Unlike Group III-V materials, germanium and tin both belong to Group IV elements. Incorporating a specific proportion of tin into the germanium lattice can change the energy band structure, turning it into a "direct bandgap" material, which has higher carrier mobility; at the same time, Group IV elements are highly compatible with existing silicon integrated circuit processes, so they have attracted much attention in the field of optoelectronic applications.

In the past, a major challenge with germanium-tin alloys was the difficulty in chemically reacting between the two elements under normal conditions. Until recently, a team from the University of Edinburgh heated a mixture of germanium and tin to 1200°C and applied a pressure of up to 10GPa, and finally successfully prepared a germanium-tin alloy that can exist stably at normal temperatures and pressures.

Whether it is a new generation of electronic equipment or a data center whose power demand continues to grow, optical transmission is expected to improve energy efficiency in the future; new materials are expected to make equipment run faster and consume less energy.

Related papers were published in the Journal of the American Chemical Society.