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Transparent conducting oxides (TCOs) are increasingly critical components in photovoltaic cells, low‐e windows, flat panel displays, electrochromic devices, and flexible electronics. The conventional TCOs, such as Sn‐doped In2O3, are crystalline single phase materials. Here, we report on In‐Zn‐O (IZO), a compositionally tunable amorphous TCO with some significantly improved properties. Compositionally graded thin film samples were deposited by co‐sputtering from separate In2O3 and ZnO targets onto glass substrates at 100 °C. For the metals composition range of 55–84 cation% indium, the as‐deposited IZO thin films are amorphous, smooth (RRMS < 0.4 nm), conductive (σ ∼ 3000 Ω−1 · cm−1), and transparent in the visible (TVis > 90%). Furthermore, the amorphous IZO thin films demonstrate remarkable functional and structural stability with respect to heating up to 600 °C in either air or argon. Hence, though not completely understood at present, these amorphous materials constitute a new class of fundamentally interesting and technologically important high performance transparent conductors.

We show that time-resolved photoluminescence measurements of completed polycrystalline CdTe solar cells provide a measure of recombination near the CdTe/CdS metallurgical interface that is strongly correlated to the open-circuit voltage in spite of complex carrier dynamics in the junction region. Oxygen in the growth ambient during close-spaced sublimation generally reduces this recombination rate; grain size does not have a strong effect.

The role of hydrogen in nitrogen-doped ZnO thin films was studied by Fourier transform infrared (FTIR) absorption and modeled by first-principles calculations to understand the difficulty of doping ZnO p-type with nitrogen. Nitrogen-doped ZnO films were fabricated by low-pressure metal-organic chemical vapor deposition (MOCVD). High levels of nitrogen incorporation were observed, but the acceptor concentrations remained low. Theoretical analysis suggests there is a high probability that NO− and H+ charged defects combine to form the neutral defect complexes, thereby compensating the nitrogen-related acceptors. Calculated values of the vibrational frequencies of the related infrared modes agree well with the measured spectra. Thus, we believe the difficulty of achieving p-type doping in MOCVD-grown ZnO films is due, at least partially, to inadvertent passivation by hydrogen.

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