Room Temperature Deposition Processes Mediated By Ultrafast Photo- Excited Hot Electrons

摘要

The goal of the DARPA Local Control of Materials Synthesis (LoCo) program is to develop a generally applicable low-temperature process for the deposition of thin films, whose current minimum processing temperature exceeds the damage threshold temperatures of substrates of interest to the DoD. Early in the program, the representative thin film material was designated to be diamond. Conventional CVD diamond deposition requires temperatures greater than approximately 700 0C, which results in severe degradation of many substrates of interest. To address this challenging scientific and technological problem, we have identified a novel approach. In this approach, wavelength specific, femtosecond laser pulses are used to control material processes, particularly growth processes, at the quantum level. Such an approach arises out of a focus on fundamental issues of non-equilibrium many-body physics that have been only recently addressed. We are pleased to report that our research team has exceeded the goals outlined for the first phase of the program and have demonstrated high-quality diamond growth at substantially lower temperatures. Our results demonstrate that this unique approach holds great promise for addressing and solving this important problem. Clearly, additional research needs to be carried out to facilitate further development and eventual implementation.