Electrical characterization of vacuum-deposited n-CdS/p-CdTe heterojunction devices

Bayhan H., Ercelebi C.

SEMICONDUCTOR SCIENCE AND TECHNOLOGY, cilt.12, sa.5, ss.600-608, 1997 (SCI İndekslerine Giren Dergi) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 12 Konu: 5
  • Basım Tarihi: 1997
  • Doi Numarası: 10.1088/0268-1242/12/5/014
  • Sayfa Sayıları: ss.600-608


The effects of post-deposition processes such as CdCl2 dip and/or annealing in air on the material and device properties of vacuum-evaporated Au-CdTe/CdS-TO heterojunction solar cells have been investigated. The CdCl2 dip followed by air annealing at 300 degrees C for 5 min improved the device efficiency significantly, resulting in decreased CdTe resistivity and enhanced grain size. The temperature-dependent current-voltage analysis indicated that above 280 K interface recombination dominates the current transport mechanism for the as-grown samples, while depletion region recombination starts to be dominant after annealing the samples with CdCl2. Below 280 K multistep tunnelling is identified to be the dominant transport mechanism. Frequency-dependent capacitance-voltage studies revealed that after annealing with CdCl2 the density of interface states decreases and the quality of the heterointerface improves. The capacitance of the CdS/CdTe heterojunctions has been analysed using a model based on the existence of a single dominant trap level, identified at 0.40 eV above the valence band with a concentration of 5.1 x 10(15) Cm-3.