Abstract
Bare surface barrier heights (BSBHs) of AlGaN∕GaN heterostructures, with varying AlGaN layer thickness and ∼35% Al alloy composition, have been measured using UV laser induced transients. The BSBH has been observed to vary with AlGaN thickness, before it saturates beyond a critical thickness, and the variation found to be very similar to that of the two-dimensional electron gas (2DEG) density at the interface. Such a trend can be explained by considering the presence of surface donor states distributed in the band gap. The density of the surface donor states has been calculated from the variation of the surface barrier with the 2DEG density, and found to be almost constant at ∼1.6×1013cm−2eV−1 in the energy range of ∼1.0–1.8eV from the conduction band. After SiNx passivation of the surface, the BSBH reduces, and sheet charge density increases, indicating the presence of positive charges in the passivation layer.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
