The effect of CdTe growth temperature and ZnTe:Cu contacting conditions on CdTe device performance

J. M. Burst, W. L. Rance, T. M. Barnes, M. O. Reese, J. V. Li, D. Kuciauskas, M. A. Steiner, T. A. Gessert, K. Zhang, C. T. Hamilton, K. M. Fuller, B. G. Aitken, C. A. Kosik Williams

Research output: Chapter in Book/Report/Conference proceedingConference contribution

13 Citations (Scopus)


CdTe device performance is strongly dependent on the quality of the back contact and the ability of the back contact to introduce a copper doping profile in the CdTe layer itself. Copper-doped ZnTe (ZnTe:Cu) is a nearly ideal contact material for CdTe solar cells due to its work function and ability to source copper to CdTe. Most of the ZnTe:Cu studies in the past used CdTe grown at relatively low deposition temperatures (550°C and below). Here we investigate the use of ZnTe:Cu as a back contact for CdTe grown at temperatures up to 620°C. We observe a strong interplay between the CdTe absorber deposition conditions and optimized ZnTe:Cu contacting conditions. Device JV characteristics suggest that CdTe solar cells with absorber layers deposited by close-space sublimation (CSS) at high temperature, 600-620°C, are more robust to the back contact Cu doping level and contacting temperature than CdTe grown at lower temperatures. The implication for industrial processes is a ∼1% absolute increase in device efficiency for devices in which the CdTe is deposited on PV glass at high temperature. Perhaps more importantly, this increased performance is maintained for a larger window of temperature and doping level of the ZnTe:Cu back contact. For devices with CdTe absorbers deposited at 600°C, device efficiency in excess of 13.5% is maintained for back contacts containing 2-5 wt.% Cu, and for contacting temperatures ranging from 300-360°C. Red-light bias quantum efficiency (QE) and capacitance-voltage (CV) measurements are used to probe the effect of the introduced copper doping profiles and net acceptor density to better understand how ZnTe:Cu sources influences the resulting CdTe device.

Original languageEnglish
Title of host publicationProgram - 38th IEEE Photovoltaic Specialists Conference, PVSC 2012
Number of pages4
Publication statusPublished - 2012
Event38th IEEE Photovoltaic Specialists Conference, PVSC 2012 - Austin, TX, United States
Duration: 2012 Jun 32012 Jun 8

Publication series

NameConference Record of the IEEE Photovoltaic Specialists Conference
ISSN (Print)0160-8371


Other38th IEEE Photovoltaic Specialists Conference, PVSC 2012
Country/TerritoryUnited States
CityAustin, TX

All Science Journal Classification (ASJC) codes

  • Control and Systems Engineering
  • Industrial and Manufacturing Engineering
  • Electrical and Electronic Engineering


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