Many days ago, I was introducing graphene to my undergraduate students. One student ask me a question: what are the requirements from an ideal hypothetical semiconductor? From that day I am continuously searching literature but I did not get satisfactory answer. What is your opinion in this regard?
First of all, it is necessary to determine the concept of ideal hypothetical semiconductor. It may be that this semiconductor should have a perfect crystalline structure, where completely absent both the intrinsic defects (vacancies, interstitials) and residual impurity atoms. In this case, in the band gap will be missing any energy level, caused by defects. Generation of the carriers will take place only through band-to-band transitions. Thus, there are no capture centers for carriers. Therefore, in such semiconductors will have a scattering of carriers only by vibrations of the crystal lattice. This initial idea of such semiconductors. Then the properties of these semiconductors can be developed further. Of course there may be other options above semiconductors. I present one of them (in terms of crystal structure).
Very good question but unfortunately, I haven't satisfactory response. Because the ultimate requirements depend on the given application.
Yes you are right, but let look on the other way, Is it possible one semiconducting material can be optimized for highly efficient electronic devices? If yes, then what we expect from such semiconducting material.
First of all, it is necessary to determine the concept of ideal hypothetical semiconductor. It may be that this semiconductor should have a perfect crystalline structure, where completely absent both the intrinsic defects (vacancies, interstitials) and residual impurity atoms. In this case, in the band gap will be missing any energy level, caused by defects. Generation of the carriers will take place only through band-to-band transitions. Thus, there are no capture centers for carriers. Therefore, in such semiconductors will have a scattering of carriers only by vibrations of the crystal lattice. This initial idea of such semiconductors. Then the properties of these semiconductors can be developed further. Of course there may be other options above semiconductors. I present one of them (in terms of crystal structure).
I think Intrinsic semiconductors without any dopant species present such as Silicon (Si) are good example for students. In intrinsic semiconductors the number of excited electrons is equal to the number of holes n=p, these semiconductors are often called i-type semiconductors. Based on the application addition of boron or phosphorus as impurities to i-type Si will make it p-type (contains excess holes) or n-type (contains excess electrons) semiconductors.
Your aim is may be the device performance. If this is the case, the performance depends on the material parameters (carrier concentration, mobility, lifetime, transparency, etc..
Improving the parameters can lead to conflicting results. In this situation, you must use approaches often complex. many concept exist, we propose a new approch for the TCOs in the article below.
See article: Pareto-optimal transparent conductive oxides
An ideal semiconductor will be one that has a zero on-state resistance, infinite transition capabilty, instantaneous switching/commutation and, if it's a controlled device (such as a BJT, Mosfet, IGBT etc), draws zero current on the gate/base.
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science
- Materials
- Nanomaterials