Ammonium sulfide surface treatment of electrodeposited p-type cuprous oxide thin films

Surface treatment of electrodeposited n‐type Cu2O thin films for applications in Cu2O based devices

“…However, evidence of using sulfur treatment to passivate the Cu 2 O film surfaces is not available in literature even though cyanides and hydrogen have been used for the passivation of p‐type Cu 2 O film surfaces 13, 14. Recently, we have demonstrated the use of (NH 4 ) 2 S assisted sulfur treatment for the enhancement of optical and electrical properties of p‐type Cu 2 O thin films 15. Similar experiments were carried out in order to study the effect of sulfur treatment on n‐type Cu 2 O thin films fabricated using electrodeposition.…”

Annealing effects of the untreated and sulfur-treated electrodeposited n-type and p-type cuprous oxide thin films

“…To passivate the film surfaces, (NH 4 ) 2 S vapor treatment was used by simply holding the Cu 2 O film face down above a beaker containing 20 vol% (NH 4 ) 2 S solution for n‐type and 50 vol% (NH 4 ) 2 S solution for p‐type at 27 °C, followed by rinsing immediately with distilled water. Detailed experimental procedure has been discussed elsewhere . In order to make the spectral response measurements, all sulfur‐treated Cu 2 O thin films were investigated in a three electrode photoelectrochemical cell containing a 0.1 M sodium acetate solution.…”

“…Some of the key issues that need to be addressed in Cu 2 O thin film solar cell development is the associated high resistivity and defects of the Cu 2 O thin films. For device applications, especially, the minimization of surface defects such as those due to dangling bonds and nonradiative recombination centers in the Cu 2 O films is of utmost importance because it causes to reduce resistivity and enhance the electrical and optical properties . An obvious approach to modify surface and interface properties of semiconductors is to make the surface interact with foreign atoms, e.g., sulfur , selenium , chlorine , or simple radicals, e.g., cyanides .…”

“…Studies conducted by us on passivation of n‐Cu 2 O and p‐Cu 2 O thin films using ammonium sulfide have demonstrated that the film resistivity can be lowered while increasing the photoactivity of the related thin film solar cell structures. It was shown that the increase in the peak photocurrent was approximately a 50‐fold and 4‐fold, respectively, compared to the untreated n‐type Cu 2 O and p‐type Cu 2 O films . The passivation along with annealing was successfully used to improve the efficiency of Ti/p‐CuO/n‐Cu 2 O/Au solar cell.…”

“…Further studies with regard to structural and thermal stability of passivated and annealed Cu 2 O thin films will provide important information for improving the performance of such devices. Previously, it was verified that the sulfur passivation of both n‐Cu 2 O and p‐Cu 2 O thin films using ammonium sulfide led to the formation of Cu x S. However, the nature of the so formed Cu x S was not able to be examined by laboratory X‐ray diffraction which has limitations in providing complete information when the thin films consist of species in the form of very thin layers or dilute quantities. This can be circumvented by the use of high‐energy X‐ray diffraction (HEXRD) in which the diffraction data of high signal to noise ratio is capable of divulging structural information in a more accurate manner.…”