Betavoltaic Device with Enhanced Performance using WBG (Al)GaN Nanostructures
Abstract
The objective is to grow wide bandgap (Al)GaN nanostructures for increased current generation in III-Nitride based betavoltaic stmctures. High quality p-type (Al)GaN will first be epitaxially grown on Si or Sapphire substrates. Plasma enhanced CVD (PECVD) will be used to deposit about l OOnm of Si02 or SiNx dielectric mask on p-type film. Lithography will be done to define patterns with lateral dimension of >500mn, followed by ICP dry etching to open windows into the dielectric for subsequent regrowth of p-GaN pillars. Conformal growth of n+ (Al)GaN will complete the epitaxy. The thickness of n+ layer will be optimized to achieve the highest current. The doping density of the nanoshuctures will also be optin1ized for inaxitnum charge carrier collection. The doping density in the p-core and n-shell will be adjusted and optimized based on the conditions of planar n- and p-GaN layers. SIMS will be used to estimate the doping density and selected nanostructures will be characterized using TEM to assess defect density. Conformal growth of n+-GaN on the p-GaN cores in systematic experiments will be done to enhance junction integrity and minority carrier diffusion lengths. The highly textured surface area of the battery will need to be confonnally encased in isotope fuel to demonstrate the direct conversion capability of the GaN based nanostructured junctions. Devices will be fabricated and their characteristics will be compared with planar p-(i)-n devices under similar doping density and alloy composition.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 12, 2017
- Source ID
- W911NF1510550
Entities
People
- Fatemeh Shahedipour-sandvik
Organizations
- Army Contracting Command
- Research Foundation for the State University of New York
- United States Army