Abstract: According to one embodiment, a position sensitive detector (PSD) comprises a plurality of layers, including a substrate layer, an absorber layer, a barrier layer, a sheet layer, and a contact layer. The absorber layer absorbs incident photons such that the absorbed photons excite positive charges and negative charges in the absorber layer. The barrier layer collects a photocurrent from the absorber layer, the photocurrent comprising either the positive charges or the negative charges. The sheet layer provides resistance to control the flow of the photocurrent between a point of incidence of the photons and a plurality of interconnect contacts. The contact layer comprises the interconnect contacts, each interconnect contact operable to conduct the photocurrent to one or more electrical components external to the PSD. The position sensitive detector facilitates determining the point of incidence of the photons according to a relative amount of photocurrent associated with each interconnect contact.

Abstract: Apparatus and method for synthesizing nanostructures in a controlled process. An embodiment of the apparatus comprises a stage or substrate holder that is heated, e.g., resistively, and is the primary source of heating for the substrate for nanostructure synthesis. The substrate and substrate heater are enclosed in a chamber, e.g., a metal chamber, which is ordinarily at a lower temperature than are the substrate and substrate heater during synthesis. Some embodiments of the invention are particularly useful for chemical vapor deposition (CVD), low pressure CVD (LPCVD), metal organic CVD (MOCVD), and general vapor deposition techniques. Some embodiments of the present invention allow for in situ characterization and treatment of the substrate and nanostructures.