Basic research needs and opportunities in thin films and coatings

Abstract

A close link must be established between the basic research community and the solar product and user community in order to maximize our understanding of thin film processing technologies and the principal mechanisms for environmental degradation, as well as the technology transfer of this necessary understanding into commercial manufacturing operations. To this end we propose objectives for necessary thin film solar-related research, namely (1) to gain a better understanding of basic processes involved in thin film fabrication, (2) to determine process parameters and the relationship of process parameters to thin film properties and (3) to develop better methods for characterizing the product film or coating in terms of relevant materials properties and product degradation modes. Discussion is divided into three areas corresponding to these objectives. In the section on fundamental mechanisms of film deposition and growth (Section 3.1) a number of significant basic processes occurring in film growth, all of which need further study, are listed and also the need for analytical techniques to study these processes is discussed. In the section on deposition process characterization and control (Section 3.2), several deposition techniques are described in some detail ranging from MBE, carried out in a highly controlled ultrahigh vacuum environment, to CVD, carried out in a more complex less well-characterized environment. Advantages and disadvantages of each are discussed. In the section on product characterization (Section 3.3) the need for developing clear-cut diagnostic techniques specific to the solar performance of a thin film material is discussed as well as the need for studying mechanisms of environmental degradation of solar films. The need for in situ characterization during the film or coating process, which can be fed back to control deposition parameters and thus can maximize product quality and uniformity, is emphasized. In the final section (Section 4), specific topics of research are presented that were determined by consensus to be of greatest priority to solar thin film devices. In the appendix we provide the basic researcher with background information about some specific solar thin film problem areas. © 1982.