Semiconductor nanowires: a platform for exploring limits and concepts for nano-enabled solar cells

Abstract

Abstract:Over the past decade extensive studies of single semiconductor nanowire and nanowire array photovoltaic devices have explored the potential of these materials as platforms for a new generation of efficient and cost-effective solar cells. This feature review discusses strategies for implementation of semiconductor nanowires in solar energy applications, including advances in complex nanowire synthesis and characterization, fundamental insights from characterization of devices, utilization and control of the unique optical properties of nanowires, and new strategies for assembly and scaling of nanowires into diverse arrays that serve as a new paradigm for advanced solar cells. 2 Table of Contents Entry:Advanced synthetic control over the electronic and optical properties of semiconductor nanowires enables testing new paradigms for advanced solar cells. Broader Context Box:The solar power received by the earth dwarfs global power demands by several orders-ofmagnitude. Photovoltaics convert light to electrical energy and have the potential to partially replace current energy technologies that rely on carbon-based fuels. At present, however, a lack of infrastructure and the high costs of photovoltaics prevent this. New ideas and materials are being explored to develop next-generation solar cells that could operate more efficiently and cheaply. Nanowires have emerged as one promising platform to explore such new concepts.Their small dimensions allow for efficient charge separation and light absorption properties unique as compared to bulk materials. Furthermore, the synthesis and fabrication of nanowire devices differs significantly from traditional wafer-based technologies, thus presenting new opportunities such as use of less abundant materials or cheaper substrates. Here, we discuss the benefits and remaining challenges of nanowires for PV and review progress towards understanding and optimizing the electrical and optical performance of nanowire devices. We focus on single nanowire studies that can define limits for what is achievable when multiple nanowires are assembled. Challenges and initial progress towards scaling are presented, and, for the first time, we articulate unique capabilities of solar cells derived from multiple, distinct NWs. 6

Production of three-dimensional quantum dot lattice of Ge/Si core–shell quantum dots and Si/Ge layers in an alumina glass matrix

“…Ge/Si nanowires with core/shell structure are also extensively studied both theoretically and experimentally [7,8,9,10,11,12].…”

Nanowire Lasers

“…In addition, bottom-up growth can yield nearly defect-free, single-crystal heterostructures on virtually any kind of substrate, thus tremendously increasing the spatial design parameters. This unique combination of geometric and material properties (see for recent examples [20,48]) is therefore very attractive for developing highly integrated laser sources that, besides optical data transmission, can be used for sensing, imaging, and many other applica- GaN with a photoluminescence spectrum at 1 mW continuous wave excitation (black) and lasing with pulsed 1 nJ/cm 2 excitation (blue) (adapted with permission [45]). (b) GaAs nanowire with transition spectra from spontaneous emission with 144 µJ/cm 2 per pulse (green) and 202 µJ/cm 2 per pulse (orange) to stimulated emission with 240 µJ/cm 2 per pulse (red) and 288 µJ/cm 2 per pulse (brown) (adapted with permission [87]).…”

Tunable electronic properties of silicon nanowires under strain and electric bias

“…C Semiconducting nanowires (NWs) are basic building blocks for the function and integration of nanoscale devices such as nanoswitches, single electron transistors, optoelectronic units, sensors, and solar cells. [1][2][3][4][5][6][7][8][9][10] Silicon nanowires (SiNWs) are prototype semiconducting wires that have attracted a great deal of attention. 11 They have been found to have more advantageous catalytic properties than palladium or gold.…”