Photoluminescence of CuInS2 thin films and solar cells modified by postdeposition treatments

Abstract

The photoluminescence of CuInS2 thin films and solar cells is investigated as a function of postdeposition treatments for different temperatures and excitation intensities. Annealing in hydrogen atmosphere causes an increase of PL intensity at 1.445 eV by more than a factor of 100, while subsequent annealing in oxygen or air ambient passivates this transition, which is ascribed to a donor-acceptor pair recombination between a sulphur vacancy and a copper vacancy. A defect mechanism is suggested that assumes the passivation of sulphur vacancies by oxygen in grain surfaces which can be activated by hydrogen annealing.

Spray CVD of Single‐Source Precursors for Chalcopyrite I–III–VI2 Thin‐Film Materials

“…This is probably from the combination of excitonic recombination and other transitions associated with unidentifi ed shallow defect levels. 68 Clear differences between the leading and trailing edges were observed from emission bands associated with deeper defect levels. For the trailing edges, the intensities of PL3 at 1.37 eV were always higher than those of PL4 at 1.32 eV (Fig.…”

“…The blueshifts were attributed to donor -acceptor pair (DAP) recombination. 68,69 PL2 did not show any excitation power dependency, whereas the analysis of the PL4 band was not attempted because of the uncertainty in its precise location. The effect of increasing excitation intensity can be clearly observed in Fig.…”

“…68 When the excitation energy increases, the fi lm is fl ooded with photogenerated carriers. As a result, the average separation between the donor and the acceptor decreases, causing the blueshift.…”

On the homogeneity region, growth modes and optoelectronic properties of chalcopyrite‐type CuInS2

“…No assignment nor explanation was found in the literature to explain the DA pairs at 1.372 eV and at 1.41 eV so far. They seem to be specific for copper sulphide-rich materials [25].…”

Aerosol-Assisted Chemical Vapor Deposited Thin Films for Space Photovoltaics

“…This is probably due to the combination of excitonic recombination and other transitions associated with unidentified shallow defect levels (ref. 27). Clear differences between the leading and trailing edges were observed from emission bands associated with deeper defect levels.…”