Como criar um novo material semicondutor?

The crystal structure influences electronic properties and also determines how the fabrication process will be (whether it will be tough or simple). Choosing a crystal structure for a semiconductor involves considering the application's requirements. Common structures like zinc blende and wurtzite offer different properties. Zinc blende, characterized by cubic symmetry, is favoured for its isotropic nature and ease of fabrication. It is commonly associated with III-V compound semiconductors like GaAs. Wurtzite has hexagonal symmetry and is prevalent in II-VI compound semiconductors like ZnS. It has anisotropic properties, meaning its characteristics vary with crystallographic direction. This can impact the performance of electronic devices.

Semiconductors, which are an essential part of solar research, are materials that have a crystalline structure. This means that the covalent bonding in these materials is such that the atoms form a periodic atomic structure.

The choice of crystal structure is pivotal as it sets the foundational properties of the semiconductor. For instance, silicon's diamond crystal structure is a key factor in its dominance in the semiconductor industry due to its balanced properties such as a suitable band gap for electronics and good carrier mobility. However, emerging applications like power electronics or optoelectronics may benefit from materials like gallium nitride (GaN) with a wurtzite crystal structure, offering higher electron mobility and a wider band gap.

Selecting a semiconductor material involves defining the purpose, choosing elements or compounds based on electronic properties, and considering factors like band-gap, crystal structure, and doping for conductivity control. Consider the band-gap based on application needs (wide for high frequency, narrow for infrared). For specific applications like transistors or solar cells, determine the desired band-gap and crystal structure. Consider doping for conductivity control, ensuring compatibility with other materials, and factor in cost, availability, and environmental impact. Theoretical models should be used for insights, experiment with compositions, optimize based on results, and validate through testing.

The most used semiconductor materials are silicon, germanium, and gallium arsenide. Of the three, germanium was one of the earliest semiconductor materials used. Germanium has four valence electrons, which are electrons located on the outer shell of the atom

Characterizing semiconductor materials involves techniques like X-ray Diffraction (XRD) for crystal structure Scanning Electron Microscopy (SEM) for surface morphology Transmission Electron Microscopy (TEM) for nano-scale structure. Energy Dispersive X-ray Spectroscopy (EDS) determines elemental composition, while Fourier Transform Infrared Spectroscopy (FTIR) and Raman Spectroscopy analyse chemical bonding. Hall Effect Measurement gauges carrier properties, and electrical characterization assesses conductivity. Photoluminescence Spectroscopy examines emitted light for band-gap and defects. Ellipsometry determines optical properties and film thickness. Combining these all we get its physical, chemical, and electrical characteristics

Testing semiconductor materials is critical to ensure that the new material meets the desired specifications and can withstand real-world conditions. It's important to note that testing often requires a multidisciplinary approach, combining electrical engineering, materials science, and physics to accurately assess device performance. Furthermore, environmental testing, such as temperature and humidity stress, is also essential to evaluate the material's stability and longevity under various operating conditions.

Creating a new semiconductor material is a complex process that intertwines physics, chemistry, and engineering. Each step, from choosing a crystal structure to testing a device, requires precision and innovation. For instance, selecting a composition isn't just about the elements involved, but understanding how their electronic properties will interact under various conditions. Synthesis methods must account for the scalability and reproducibility of the material. Characterization goes beyond basic properties, delving into defects and interfaces that can drastically affect performance. Testing in a device context reveals real-world applicability, and publishing results contributes to the collective knowledge, driving the industry forward.