One-dimensional Si/Ge nanowires and their heterostructures for multifunctional applications—a review

Abstract

Remarkable progress has been made in the field of one-dimensional semiconductor nanostructures for electronic and photonic devices. Group-IV semiconductors and their heterostructures have dominated the years of success in microelectronic industry. However their use in photonic devices is limited since they exhibit poor optical activity due to indirect band gap nature of Si and Ge. Reducing their dimensions below a characteristic length scale of various fundamental parameters like exciton Bohr radius, phonon mean free path, critical size of magnetic domains, exciton diffusion length etc result in the significant modification of bulk properties. In particular, light emission from Si/Ge nanowires due to quantum confinement, strain induced band structure modification and impurity doping may lead to the integration of photonic components with mature silicon CMOS technology in near future. Several promising applications based on Si and Ge nanowires have already been well established and studied, while others are now at the early demonstration stage. The control over various forms of energy and carrier transport through the unconstrained dimension makes Si and Ge nanowires a promising platform to manufacture advanced solid-state devices. This review presents the progress of the research with emphasis on their potential application of Si/Ge nanowires and their heterostructures for electronic, photonic, sensing and energy devices.

Self-powered ZnS Nanotubes/Ag Nanowires MSM UV Photodetector with High On/Off Ratio and Fast Response Speed

“…Besides, the fully nanostructured PDs concept using the ZnS NTs network as active layer and Ag NWs network as electrodes allows the fabrication of devices through economic and wide scale available methods and display great potential in large area electronics that are flexible and transparent 26–29 . The performance analysis of the as-fabricated device demonstrates a high on/off ratio of 19173 and a fast response speed (τ r  = 0.09 s, τ f  = 0.07 s) without any external bias.…”

Coulomb blockade in monolithic and monocrystalline Al-Ge-Al nanowire heterostructures

“…Among them, considerable effort has been devoted to fabricate quasi-1D nanostructures such as vapor-liquid-solid (VLS) [7] grown nanowires enabling the customization of morphology, geometry, composition or crystal orientation. Recently, band-structure engineering by controlled epitaxial growth of core-shell NWs provoked the investigation of one-dimensional hole-gas systems [8], attractive for both fundamental studies and future nanoelectronics [9]. Despite the vast body of pioneering experimental work on GeSi [10] and Ge-Si core-shell structures [11,12] the investigation of Coulomb blockade effects in pure Ge based nanostructures is still evasive.…”

Highly Transparent Contacts to the 1D Hole Gas in Ultrascaled Ge/Si Core/Shell Nanowires

“…2,3,4 Especially band-structure engineering by controlled epitaxial growth of core/shell NWs provoked the investigation of 1D hole-gas systems, 4 attractive for fundamental studies of low-dimensional transport as well as future high-performance nanoelectronic or quantum devices. 5,6,7,8,9 Further, heterostructures of dissimilar materials with unique structure-property relationships and interactions originating from the contributions of individual low-dimensional components may enable novel electronic or photonic devices that are outclassing or even unattainable for planar geometries. 10,11 However, fabricating interconnects is a crucial step towards the integration of such future ultra-scaled devices and requires sophisticated nanostructure formation techniques and precise lithography.…”