|About this Abstract
||Materials Science & Technology 2009
||Characterization and Modeling of Ceramic-Ceramic and Metal-Ceramic Interfaces
||First Principles Study of GaN-GaN Junctions with Ultrathin AlN Interlayers
||Rohan Mishra, Oscar Restrepo, Siddharth Rajan, Wolfgang Windl
|On-Site Speaker (Planned)
GaN-GaN junctions with ultrathin AlN interlayers are being looked upon as candidates for high-frequency, high-power transistors and light emitting devices that can be operated in the deep UV region. As these heterostructure based devices are shrinking to a few monolayers in thickness, it has become imperative to study their properties at such a small scale. We report an <I>ab-initio</I> density functional theory study of the effect of surface charges on the band behavior and polarization in these heterojunctions. The layer-projected density of states indicates that geometry optimization is necessary to get the correct band-bending. Interestingly the bulk polarization values that allow the formation of a two-dimensional electron gas at the interface are found to be valid to a few monolayers of AlN. At such small thicknesses, surfaces are found to have a strong impact on the energy bands such that the conduction band minima and valence band maxima overlap.