Polycrystalline n ‐ZnO/ p ‐Cu ₂ O heterojunctions grown by RF‐magnetron sputtering

Abstract

PACS 73.61. Ga, 81.15.Cd, 84.60.Jt Polycrystalline n-ZnO/p-Cu 2 O heterojunctions were fabricated by reactive sputtering for photovoltaic applications. Although electrical rectification was not reproducibly obtained in the as-grown samples, rectification was observed in the samples fabricated with cyanide treated Cu 2 O. We have previously shown that cyanide treatment has an effective role in passivation of defects in Cu 2 O, in analogy to hydrogen passivation. It is, therefore, believed that the observed improvement in the electrical rectification of the ZnO/Cu 2 O heterojunctions is attributable to the defect passivation near the hetero-interface. The effectiveness of the cyanide treatment and the importance of defect passivation in ZnO/Cu 2 O heterojunctions are presented.

Epitaxial growth of Cu2O and ZnO/Cu2O thin films on MgO by plasma-assisted molecular beam epitaxy

“…The approach taken in this paper anticipates the use of n-ZnO as the heterojunction partner for p-Cu 2 O in photovoltaic devices. There have been many reports on Cu 2 O solar cells prepared by various techniques, including electrodeposition [3], thermal oxidation of copper sheets [7], and sputter deposition [8]. However, the energy conversion efficiencies of these cells were only a fraction of their respective Shockley-Queisser theoretical values.…”

“…It has been reported to have a long minority carrier diffusion length ( $ 5 mm) [2], and is also composed of both earth-abundant and inexpensive elements [3]. Cuprous oxide is typically a p-type semiconductor due to intrinsic doping by copper vacancies, and efforts to form high-quality homojunctions by n-doping of Cu 2 O have largely been unsuccessful.…”

Effect of bath concentration on the growth and photovoltaic response of SILAR-deposited CuO thin films

“…The oxides of copper such as cuprous oxide (Cu 2 O) and cupric oxide (CuO) are the two stable forms of semiconducting oxides having different crystal structures and physical properties [8,9]. The Cu 2 O has been widely studied as an absorber for low-cost solar cells [10][11][12][13][14], but its high optical band gap (2.1 eV) is not optimum to obtain high conversion efficiency in single-junction solar cells [15], whereas the CuO possesses a direct band gap of *1.3 eV, which is ideal for an absorber material to be used in solar cell applications [16,17].…”

Highly oriented polycrystalline Cu2O film formation using RF magnetron sputtering deposition for solar cells

“…Among several Cu 2 O formation methods, such as thermal oxidation [6 -12], electrodeposition [13][14][15][16][17][18][19][20][21] and sputtering deposition [22][23][24][25][26][27], the highest conversion efficiency was obtained by the thermal oxidization method. Since the thermal oxidation progresses under a thermal equilibrium state of the Cu 2 O phase [28], it seems to be an ideal formation method.…”