Thrust 2: 2015 Tandem Integration with Silicon Technologies

Co-leaders: Doolittle and Holman

Terawatt Scale III-V/Si Tandems (Atwater)

The broad objective of project is to develop a multidisciplinary research initiative designed to lead to a manufacturable low-cost III-V/Si tandem cell. Effort is focused on dual junction III-V/Si tandem cells integrated onto patterned thin Si wafers designed to facilitate both i) selective III-V epitaxy and ii) light trapping. The effort will comprise device design, patterned Si wafer design, III-V materials growth and fabrication and assessment of reliability and manufacturing issues that are important for scalability to the terawatt level.

Optimizing Metamorphic III-Sb Epitaxial Layers on Silicon using XR-HRD and TEM/ECCI (Balakrishan)

The overall objective of this project is to integrate III-Sb based compound semiconductor photovoltaic sub-cells with Si substrates to extend the spectral response of such cells in the Near IR resulting in improved efficiency. The growth of such highly mismatched, narrow bandgap antimonides on silicon substrates will be achieved through the use of a novel semiconductor epitaxial growth mode based on inducing 90° interfacial misfit dislocation arrays (IMF) between the GaSb epilayer and the silicon or GaAs substrate.

Terawatt-scale III-Nitride on Si In-situ and Induced Junctions (Doolittle)

The objective of this project is use a multidisciplinary research team’s expertise to demonstrate a manufacturable, low-cost III-Nitride on Si induced junction and/or in-situ formed junction with a dramatically lower than traditional thermal budget and with an efficiency >20% efficiency at 1 Sun. We will also explore the limitations of and the utilization of eutectic reactions with common group III metals with Si.

Dilute Nitride Materials and Devices (Freundlich)

The goal of this project is to develop quantum engineered semiconductor heterostructures and devices based on dilute nitrogen containing alloys of III-V compound semiconductors to enable improved efficiencies and manufacturability for multi-junction applications. Specifically the project aims at developing dilute nitride quantum engineered subcells to support ultra efficient yet low cost multijunction devices for concentrator and defect tolerant devices for III-V thin film PV applications.