Deep level transient spectroscopy on CuInSe2 junctions

In order to investigate defects in monocrystalline CuInSe₂ solar cells DLTS (deep level transient spectroscopy) measurements were performed on both In- or Bi-diffused homojunctions and Al-CuInSe ₂ Schottky junctions made on this material. Two hole trap levels, one at 250±15 meV and the other at 520±15 meV from the valence band edge, were found on either homojunction or Schottky junctions. The trap densities in the homojunctions were on the order of 10¹³ cm^-3, but the value was found to be one order magnitude larger in the Schottky junctions fabricated on the same substrate. During the DLTS measurements, another hole trap level with an energy of 186±3 meV from the valence band edge was found in two other Schottky junctions. The stoichiometry of the samples used to fabricate these devices was believed to be responsible for the difference