Deep Level Transient Spectroscopy and Capacitance-Voltage Measurements of Cu(In,Ga)Se2

Jehad AbuShama, Steve Johnston, Richard Ahrenkiel, Rommel Noufi

Research output: Contribution to conferencePaperpeer-review

7 Scopus Citations


The electronic properties of ZnO/CdS/Cu(ln,Ga)Se2 (CIGS)/Mo/SLG polycrystalline thin-film solar cells with compositions ranging from Cu-rich to In-rich were investigated by deep level transient spectroscopy and capacitance-voltage (C-V) measurements. This compositional change represents the evolution of the film during growth by the three-stage process. Four thinfilm CIGS samples with different Cu content were obtained. The Cu/(ln+Ga) ratio ranges from 1.24 (Cu-rich) to 0.88 (In-rich), whereas the Ga/(ln+Ga) ratio ranges from 0.19 (Cu-rich) to 0.28 (In-rich). The Cu-rich sample exhibits a shallow majority-carrier trap with an activation energy of 0.12 eV and another deeper trap with an activation energy of 0.28 eV, whereas the In-rich sample has a shallow minority-earner trap with an activation energy of 0.12 eV. The two samples show evidence of a deeper trap at higher temperature. C-V measurements showed that the average carrier concentration (N values) around the junction of the cell changed as the film transitions from Cu-rich to In-rich. DLTS shows that acceptor-like traps are dominant in samples where CIGS grains did not go through the Curich to ln(Ga)-rich transition. While donor-like traps are dominant in the ln(Ga)-rich samples.

Original languageAmerican English
Number of pages4
StatePublished - 2002
Event29th IEEE Photovoltaic Specialists Conference - New Orleans, LA, United States
Duration: 19 May 200224 May 2002


Conference29th IEEE Photovoltaic Specialists Conference
Country/TerritoryUnited States
CityNew Orleans, LA

Bibliographical note

For preprint version including full text online document, see NREL/CP-520-32205

NREL Publication Number

  • NREL/CP-520-33720


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