The overall goal of this GOALI award is to precisely engineer solar cell interfaces for improved solar energy conversion efficiency through atomic layer deposition (ALD) processes. The proposed research has the potential develop scalable manufacturing processes for ALD dipole layer coatings that precisely tailor the electronic properties of solar cell structures for increased solar energy conversion. This approach will facilitate further development of ALD methodologies for large-area coatings, which are necessary for the photovoltaics (PV) industry.
During the fabrication of solar PV materials, ALD will be used to grow conformal metal oxide dipole layers at semiconductor interfaces with controlled atomic layer thickness and uniformity, in order to adjust the band alignment for optimized charge transfer or blocking. This process has the potential to controllably enhance the photocurrent and cell voltage. Photoemission spectroscopy (PES) and inverse photoemission spectroscopy (IPES) will be used to characterize each deposited dipole layer in situ, so that the evolution of both the valence and conduction bands density of states can be followed during the ALD process. These measurements will yield a detailed picture of the evolution of the electronic structure of ALD dipole layers and interfaces as they are grown. Once the dipole layers can be grown reliably, solar cell structures with inserted dipoles will be investigated, and the performance changes will be correlated with electronic structure modification.
Broader Impacts
This GOALI research is a collaborative effort between the University of South Florida (USF) and Novellus, and major semiconductor fabrication equipment supplier. USF offers expertise in electronic structure and surface science of semiconductor PV interfaces, whereas the industrial partner Novellus offers expertise in ALD. This collaboration will focus the proposed research so that 1) industry and manufacturing relevant materials systems will be investigated, and 2) processes and intellectual property (IP) developed under this grant will find applications in industrial production settings. In addition to the potential benefits to the photovoltaics industry, the proposed activities will also train students in an industrial context. Specifically, participating graduate students will visit Novellus as summer interns, and two undergraduate students are expected to participate in the proposed research through REU supplements.
