A Review on Metastable Silicon Allotropes

Abstract

Diamond cubic silicon is widely used for electronic applications, integrated circuits, and photovoltaics, due to its high abundance, nontoxicity, and outstanding physicochemical properties. However, it is a semiconductor with an indirect band gap, depriving its further development. Fortunately, other polymorphs of silicon have been discovered successfully, and new functional allotropes are continuing to emerge, some of which are even stable in ambient conditions and could form the basis for the next revolution in electronics, stored energy, and optoelectronics. Such structures can lead to some excellent features, including a wide range of direct or quasi-direct band gaps allowed efficient for photoelectric conversion (examples include Si-III and Si-IV), as well as a smaller volume expansion as lithium-battery anode material (such as Si24, Si46, and Si136). This review aims to give a detailed overview of these exciting new properties and routes for the synthesis of novel Si allotropes. Lastly, the key problems and the developmental trends are put forward at the end of this article.

Structural Modulation and BC8 Enrichment of Silicon via Dynamic Decompression

“…Silicon (Si) as a key material in semiconductors and nanoelectronics, has drawn extensive attention for several decades. , Diamond cubic Si (Si-I, space group Fd 3̅ m ) along with its fundamental properties have been well investigated under ambient condition. − Extreme conditions, such as hydrostatic pressure, can arouse numerous phase transitions, discover extraordinary Si structures, and may further stimulate practical applications. − High-pressure studies on Si started more than 60 years ago, and since then plenty of novel Si allotropes have been reported by using diamond anvil cells (DAC). ,, …”

Thermal conductivity of fivefold twinned silicon-germanium heteronanowires

“…Silicon (Si) is a highly versatile material that has found promising applications in various modern technologies, including battery anodes, 1-3 solar cells, [4][5][6] microelectromechanical systems (MEMS), 7,8 transistors, 9,10 and thermoelectric harvesters, due to its unique properties and advantages such as geoabundance, good engineering, low-cost production, nontoxicity, and so forth. [11][12][13] Recently, it was revealed that Si has tunable properties as its dimensionality is reduced, unlocking more opportunities for advanced technical applications. For instance, it was reported that two-dimensional (2D) Si structures can serve as high-performance anode materials for lithium ion (Li + ) batteries because their lithium intercalating capacity (42100 mA h g À1 ) surpasses that of 0D Si structures.…”

Isotope doping-induced crossover shift in the thermal conductivity of thin silicon nanowires

“…Silicon (Si) shapes our present-day technologies in battery anodes [1][2][3], solar cells [4][5][6], microelectromechanical * Authors to whom any correspondence should be addressed. systems (MEMS) [7,8], transistor [9,10], and thermoelectric harvesters because of its unique properties, as well as geoabundance, good engineering and low-cost production, nontoxicity, and so forth [11][12][13]. It is worth noting that, with the reduction in the dimensionality, the properties of Si are sharply changed, enabling more possibilities in its advanced technical applications.…”