Experiments reveal promising nitride semiconductors

Increasingly sophisticated electronic devices, such as smartphones and laptops, are raising demand for semiconductors with wider ranges of properties.

Now Fumiyasu Oba and colleagues at Tokyo Institute of Technology and Kyoto University have used calculations to screen a set of compounds for potential semiconductor candidates. The study identified 11 previously unreported materials, including the particularly promising compound calcium zinc nitride (CaZn2N2).

The researchers limit their study to nitrides because they tend to be chemically stable and can be readily made with existing techniques. Nitrogen is also a widely abundant and environmentally friendly element, but, at present, the nitrides used in industry are largely limited to gallium and indium compounds.

Based on similarities in the electronic structure, the researchers rationalised that ternary zinc nitrides would be promising compounds to consider for new semiconductors in this field.

The researchers highlight the previously unreported semiconductor CaZn2N2, which should have a high electrical conductivity and a strong interaction with light. These properties are indicators of good performance in optoelectronic applications such as light emitting diodes (LEDs) and solar cells. It is also made entirely of earth-abundant elements and so can be relatively cheap to make.

Synthesis of the material using high-pressure techniques confirmed the hypothesised properties and also revealed red luminescence even at room temperature; thereby validating the study's approach.

The paper also shows that other earth-abundant materials, such as calcium magnesium nitride, can be used to tune the electrical properties of CaZn2N2, further increasing the eligibility of this material for use in devices.