Ricerc@Sapienza

This activity stems from recent achievements of the team of our Department (DIET) on the possibility to obtain nanometric islands of a crystallographic exotic phase of silicon, called Si-III or Si-BC8, diluted in the Si-I or diamond phase of silicon. Si-BC8 phase is mainly appealing because of its electrical and optical features. Indeed, the bulk Si-BC8 phase, obtained in the past mechanically by anvil press on diamond silicon, is known to be a semiconductor with a direct and narrow bandgap (30 meV). The innovative aspect of our method is in obtaining the Si-BC8 phase at low temperature, with a non-destructive planar process fully compatible with the scalability requirements for microelectronics. All these characteristics make our synthesized material amenable for optoelectronic integrated circuit applications in the infrared range of Terahertz (THz). The present one-year project has two main goals: 1) evaluate the possibility to induce Si-BC8 formation with alternative metal species; 2) design and fabricate a THz detector proof of concept. As far as the first goal is concerned, let us mention that, to date, we obtained the Si-BC8 in a microwave-CVD chamber at the Centro per le Nanotecnologie applicatate all¿Ingegneria della Sapienza (CNIS) using Sn as catalyzer metal: in this project we aim to evaluate alternative metal species to Sn for the Si-BC8 synthesis. In the second goal, we plan to pattern the metal spatial distribution on the silicon wafer surface by photolithographic techniques (performed at the DIET clean room) in order to control the Si-BC8 one. The opportunity to control Si-BC8 spatial distribution could pave the way for a THZ detector proof of concept fabrication. The technology steps will be carried out at the DIET and at the CNIS. The optical measurements will be performed at the CNR laboratory in Pisa, where the team has fruitful scientific contacts.