No abstract

Films of CdSe(ZnS) colloidal nanocrystalline quantum dots (NQDs) were deposited on bare silicon, glass and polymer coated silicon using mist deposition. This effort is a part of an exploratory investigation in which this deposition technique is studied for the first time as a method to form semiconductor NQD films. The process parameters, including deposition time, solution concentration and electric field, were varied to change the thickness of the deposited film. Blanket films and films deposited through a shadow mask were created to investigate the method's ability to pattern films during the deposition process. The differences between these deposition modes in terms of film morphology were observed. Overall, the results show that mist deposition of quantum dots is a viable method for creating thin, patterned quantum dot films using colloidal solution as the precursor. It is concluded that this technique shows very good promise for quantum dot (light emitting diode, LED) fabrication.

This experiment is concerned with photoconductive decay (PCD) measurements devised specifically for the purpose of characterization of the near-surface region of semiconductor substrates. The method was tested through the measurements of the germanium wafers for which the surface was roughened in a controlled fashion, and multi-crystalline silicon wafers with textured surfaces. The near-surface lifetime of minority carriers and carrier mobility were reduced as the Ge surface roughness increased, and increased for mc-Si as saw damage was removed by chemical treatment. These results demonstrate a direct correlation between condition of the semiconductor surface and the electrical parameters measured. It is postulated that the PCD method using temporary contact can be effectively used to monitor the condition of semiconductor surfaces during device processing.