Abstract: A semiconductor structure includes a substrate and a semiconductor channel layer over the substrate. The semiconductor structure includes a high-k gate dielectric layer over the semiconductor channel layer, a work function metal layer over the high-k gate dielectric layer, and a bulk metal layer over the work function metal layer. The work function metal layer includes a first portion and a second portion over the first portion. Both the first portion and the second portion are conductive. Materials included in the second portion are also included in the first portion. The first portion is doped with silicon at a first dopant concentration, and the second portion is not doped with silicon or is doped with silicon at a second dopant concentration lower than the first dopant concentration.

Abstract: Provided is a composite powder used for the visible light catalytic and anti-bacterial purposes. The composite powder includes a plurality of N-type semiconductor particles and a plurality of P-type semiconductor nano-particles. The P-type semiconductor nano-particles cover surfaces of the N-type semiconductor particles respectively. A weight ratio of the N-type semiconductor particles and the P-type semiconductor nano-particles is in a range of 1:0.1 to 1:0.5. A PN junction is provided between each of the N-type semiconductor particles and the corresponding P-type semiconductor nano-particles.