Superlattices are artificially created structures consisting of alternating thin layers of different semiconductor materials, typically just a few nanometers thick. These layers are arranged in a periodic fashion, forming a new material with unique electronic, optical, and quantum properties.
Key Characteristics:
- Band Structure Engineering: By carefully choosing the materials and layer thicknesses, scientists can tailor the electronic band structure, creating mini-bands and band gaps that do not exist in the individual materials.
- Quantum Confinement: Electrons and holes are confined in the potential wells formed by the layers, leading to quantum well effects.
- Bragg Reflection: The periodicity can cause reflection of electron waves, much like how X-rays reflect in a crystal, affecting electron mobility and behavior.
Applications:
- High-speed and high-frequency devices: Such as quantum cascade lasers, resonant tunneling diodes, and infrared detectors.
- Thermoelectric materials: Superlattices can reduce thermal conductivity while maintaining electrical conductivity, enhancing performance.
- Spintronics and quantum computing: Due to precise control of electron spin and movement.
Superlattices are a cornerstone of nano-engineered materials, offering extraordinary control over charge carrier dynamics and enabling cutting-edge advancements in modern electronics and optoelectronics.