Interface effects in Cu₂S-CdS photovoltaic cells formed by the dry barrier process

Abstract

Cu2S-CdS photovoltaic cells have been produced on single crystal CdS substrates using the dry barrier process. Measurements of their current-voltage characteristics the spectral distribution of the photovoltaic response, and the infrared quenching of photocapacitance have been used to evaluate effects occurring at the interface and in the depletion region of the CdS, in cells heated in oxidising and reducing atmospheres to enhance their efficiency. The photocapacitance studies show that copper diffused into the CdS and produced deep acceptors, with hole ground and excited states 1.1 and 0.35 eV above the valence band. Evidence was obtained which suggests that heating in air leads to acceptor-like states at the interface, 0.2 eV below the conduction band. The measured copper profile in the CdS was anomalous, and indicates that more than one diffusing species was active.

Ion Exchange in Ultrathin Films of Cu2S and ZnS under Atomic Layer Deposition Conditions

“…Furthermore, exposure of ZnS to bis(N,N′-disec-butylacetamidinato)dicopper(I) {[Cu( s Bu-amd)] 2 , Cu 2 DBA}, a Cu(I) ALD precursor − for Cu 2 S, at low temperature results in the conversion of ZnS into Cu 2 S and further results in the removal of Zn from the film. Ion exchange has been studied in solvated ionic systems − and at solid–solid interfaces, , but only preliminary reports have been made (for the CdS/ZnS ALD system) of ion exchange at gas–solid interfaces . Moreover, such a dramatic exchange resulting in conversion of an entire film, to our knowledge, has not been reported in the ALD literature.…”

Improvement of CdS?CuxS Solar Cell Performance by CdS Etching under Illumination

“…This is well established because the responses in the region O• 60 to 0•70 J.tm resulting from the copper levels in CdS diminish at. low temperature, whereas those due to the CUreS phases are enhanced (Pande et al 1983;AI-Dhafiri 1988). The small peak at 0•50 J.tm for the dark etched device confirms that the copper sulfide phase is djurleite (CUI.96S) rather than chalcocite (Cu2S).…”

“…Since the original observation of the photovoltaic effect induced by the p-n junction in CdS by Reynolds et al (1954), the CdS-Cu2S heterojunction has been considered an efficient photovoltaic cell for solar energy conversion over the last three decades. Many significant advances have been made in the development and understanding of these photovoltaic cells (Pande et al 1983;Oktik et al 1983;. The optical and electrical characteristics of the junction are highly influenced by the various preparation conditions.…”

AC conductivity and dielectric studies of Cd0.8Sn0.2S thin films

“…CdS is an n‐type semiconductor with a direct band gap of 2.4 eV, which falls in the visible spectrum at room temperature. Because of its wide band gap, CdS thin films are regarded as one of the most promising materials for heterojunction thin film solar cell; it has also immense potential applications in optoelectronics, such as photodetectors, LEDs, gas detectors, photovoltaic cells, and thin film transistors . One of the goals to improve the structural response of CdS is to increase its structural activity by doping with special atom.…”