Compound Semiconductors

Compound semiconductors are crystalline materials formed by elements from two different groups of the periodic table, most commonly groups III and V (for example GaAs, InP) or groups II and VI (for example CdTe, ZnO). Their defining feature is the combination of disparate cations and anions into a single lattice, yielding a rich variety of band‐gap energies, carrier mobilities and optical properties not accessible in elemental semiconductors such as silicon. Many III–V and II–VI materials exhibit direct band gaps, making them ideal for light‐emitting diodes, laser diodes and high‐efficiency photodetectors. Wide‐bandgap members (for example GaN, SiC and Ga₂O₃) sustain high breakdown fields and operate at elevated temperatures and powers, thus finding roles in power electronics, radio‐frequency amplifiers and solar-blind ultraviolet sensing. Further versatility arises from the ability to form ternary and quaternary alloys (for example AlₓGa₁₋ₓAs, In₁₋ₓGaₓN), which permit continuous tuning of lattice constant and band gap. Heterostructure and quantum‐well engineering underpin devices with quantum‐confined carriers, enhanced injection efficiency and tailored transport. In practice, the production of compound semiconductor devices relies on high‐quality bulk crystals and epitaxial thin films grown by techniques such as molecular‐beam epitaxy or metal–organic vapour‐phase epitaxy. Ongoing advances in material purity, defect control and heterogeneous integration with silicon aim to broaden functionality and reduce cost.

Research from Nature Portfolio

Enhanced gain and detectivity have been reported in solar-blind avalanche photodetectors based on a β-Ga₂O₃/MgO/Nb:SrTiO₃ heterostructure. By engineering the conduction‐band offset to suppress dark current while maintaining minority‐carrier flow, devices achieve avalanche gain up to 5.9×10⁵ and detectivity beyond 10¹⁶ Jones, comparable to photomultipliers. This work highlights the importance of precise heterojunction design for high-sensitivity Ga₂O₃ optoelectronics.

Ultra-wide band-gap Ga₂O₃ power diodes have also been realised through Ga₂O₃ heterojunction PN structures that exploit hole injection to induce conductivity modulation in low-doped material. These diodes attain 8.32 kV breakdown voltage with 5.24 mΩ·cm² on-resistance, yielding a power figure-of-merit of 13.2 GW cm⁻² that exceeds the one-dimensional unipolar limits of GaN and SiC. The results demonstrate the promise of Ga₂O₃ in next-generation high-voltage electronics.

Research from all publishers

Hybrid heterojunction photodetectors coupling p-type conjugated polymer PCDTBT and n-type amorphous Ga₂O₃ have realised self-powered operation for solar-blind UV detection. Owing to the built-in field at the type-II interface, the responsivity reaches 187 A W⁻¹ and detectivity 1.3×10¹⁶ Jones under 11 μW cm⁻² illumination, with sub-pA dark current and multifunctional phototransistor/self-powered modes.

An atmospheric plasma‐based atom‐selective etching process has been developed to polish β-Ga₂O₃ surfaces to atomic smoothness. By exploiting the lower etch barrier at step edges and elevated temperatures, the surface roughness (Sₐ) of (001) Ga₂O₃ is reduced from 14.8 nm to 0.057 nm in 120 s, with a removal rate of ~21 μm min⁻¹. Density‐functional theory reveals that lateral etching at atomic steps drives the effect, opening pathways to damage-free ultrawide-bandgap device fabrication.

Compound Semiconductors publication trend

The graph below shows the total number of articles in compound semiconductors across all publications each year (not limited to Nature Index journals).

Technical terms

Compound semiconductor: A crystalline material comprising two or more elements from different groups of the periodic table, often exhibiting direct band gaps and high mobilities.

Wide‐bandgap semiconductor: A material with a band gap exceeding ~2.5 eV, able to operate at high voltages, temperatures and frequencies.

Heterojunction: An interface between two semiconductor materials with differing band structures, used to control carrier injection, confinement and recombination.

Avalanche photodetector: A device that multiplies photogenerated carriers via impact ionisation under high electric fields, yielding internal gain.

Detectivity (D*): A figure of merit for photodetectors defined as the responsivity normalised by noise, with units Jones (cm Hz½ W⁻¹).

Power figure-of-merit: For power diodes, V₍BR₎²/R₍ON₎, indicating the trade-off between breakdown voltage and on-resistance.

Plasma etching: A dry process using ionised gases to selectively remove material, here applied to achieve atomic‐scale surface polishing.

References

1. Compound Semiconductor Crystals.
2. Enhanced gain and detectivity of unipolar barrier solar blind avalanche photodetector via lattice and band engineering. Nature Communications (2023).
3. Ultra-wide bandgap semiconductor Ga2O3 power diodes. Nature Communications (2022).
4. Multifunctional solar‐blind ultraviolet photodetectors based on p‐PCDTBT/n‐Ga2O3 heterojunction with high photoresponse. InfoMat (2023).
5. Towards atomic-scale smooth surface manufacturing of β-Ga2O3 via highly efficient atmospheric plasma etching. International Journal of Extreme Manufacturing (2024).