In Situ Defect Spectroscopy: Probing Dangling Bonds During a-Si: H Film Growth by Subgap Absorption

This paper describes a novel optical diagnostic that was recently introduced to the field of Si-based thin films for probing defect states such as dangling bonds in a-Si:H. This diagnostic is based on the cavity ringdown spectroscopy (CRDS) technique. When applied in situ or real time during film growth it can provide new insights into the a-Si:H film properties as well as into the fundamental surface processes during growth. In this paper the CRDS technique is described and both the ex situ application on as-deposited a-Si:H films as well as the in situ application during a-Si:H film growth are presented