Obviousness

I am unable to perform an obviousness analysis of US patent 9905691 under 35 U.S.C. § 103 as requested.

The provided patent text includes a "Prior art keywords" section and a "BACKGROUND" section that discusses general concepts and models (Schottky's theory, Bardeen's model, Tersoff's model), but it does not list specific prior art references (e.g., patent numbers, publications, or other documents) that would be required to identify combinations and explain a motivation to combine them.

To conduct an obviousness analysis, I would need a list of specific prior art documents that are asserted against the claims of US9905691.