Because of recent concerns about the negative externalities of traditional fuel use on the environment and health, the issue of the household fuel transition in developing countries, from dirty fuels towards clean fuels, has received growing research attention. This paper provides an up-to-date survey of the economic literature on household fuel use in these countries. First, we present the conceptual and theoretical frameworks. Then, we discuss the empirical results that show how a wide range of factors drive the household fuel transition. Finally, we suggest priorities for policy initiatives and highlight areas of future research.

In this paper, we show the coexistence of the bipolar and unipolar resistive-switching modes in NiO cells realized using an optimized oxidation process of a Ni blanket layer used as the bottom electrode. The two switching modes can be activated independent of the cell switching history provided the appropriate programming conditions are applied. The bipolar and unipolar switching modes are discussed as driven by electrochemical- and thermal-based mechanisms, respectively. The switching versatility between these two modes is demonstrated both for large oxidized Ni films and for Ni films oxidized at the bottom of small dimension contact holes. The perspective of selecting the desired switching mode in a scaled device made in a small diameter single hole is highly attractive because the specific advantages of the two modes broaden the application scope of the cell and enable larger flexibility in terms of memory architecture.