Inline atmospheric pressure metal-organic chemical vapour deposition for thin film CdTe solar cells

• Inline metal-organic chemical vapour deposition (MOCVD) used to grow CdTe films
• Desired dopant profiles in CdTe:As achieved with inline MOCVD reactor
• Initial conversion efficiency of 11.2% was comparable to batch devices (~ 13%).
• Inline MOCVD holds a good potential for large-scale thin film photovoltaics production.

A detailed study has been undertaken to assess the deposition of CdTe for thin film devices via an inline atmospheric pressure metal-organic chemical vapour deposition (AP-MOCVD) reactor. The precursors for CdTe synthesis were released from a showerhead assembly normal to a transparent conductive oxide (TCO)/glass substrate, previously coated with a CdZnS window layer using a conventional batch AP-MOCVD reactor with horizontal flow delivery. Under a simulated illumination with air mass coefficient 1.5 (AM1.5), the initial best cell conversion efficiency (11.2%) for such hybrid cells was comparable to a reference device efficiency (~ 13%), grown entirely in the AP-MOCVD batch reactor. The performance and structure of the hybrid and conventional devices are compared for spectral response, CdTe grain morphology and crystal structure. These preliminary results reported on the transfer from a batch to an inline AP-MOCVD reactor which holds a good potential for the large-scale production of thin film photovoltaics devices and related materials.