Semiconductor devices such as LEDs and transistors are generally made up of two halves: an n-type which carries negative charge via electrons, and a p-type which moves positive charge carriers called holes that are essentially electron-voids. Both halves rely on contacts that can get electric current in and out of them with minimal loss of energy. These connections, known as ohmic contacts, have been an efficiency bottleneck in thin p-type GaN semiconductors for decades owing to their high resistance.
Now, a team led by Haitao Wang and Jia Wang at the Institute of Materials and Systems for Sustainability (IMaSS) , Nagoya University, has come up with a new way of lowering the resistance of p-type GaN contacts. They deposited an ultrathin magnesium layer onto the p-GaN surface and gave it a heat treatment at 600 degrees Celsius for five minutes, thereby achieving a contact resistivity of (1–3) × 10⁻⁴ Ω cm² without damaging the surface. This is among the lowest reported contact resistivities for thin p-type GaN.
Their findings, which are expected to make a wide range of electronic devices used in places such as electric vehicles and data centers more energy-efficient, have been published in the journal Applied Physics Letters .
