Resonant Germanium Nanoantenna Photodetectors

Abstract

On-chip optical interconnection is considered as a substitute for conventional electrical interconnects as microelectronic circuitry continues to shrink in size. Central to this effort is the development of ultracompact, silicon-compatible, and functional optoelectronic devices. Photodetectors play a key role as interfaces between photonics and electronics but are plagued by a fundamental efficiency-speed trade-off. Moreover, engineering of desired wavelength and polarization sensitivities typically requires construction of space-consuming components. Here, we demonstrate how to overcome these limitations in a nanoscale metal-semiconductor-metal germanium photodetector for the optical communications band. The detector capitalizes on antenna effects to dramatically enhance the photoresponse (>25-fold) and to enable wavelength and polarization selectivity. The electrical design featuring asymmetric metallic contacts also enables ultralow dark currents (approximately 20 pA), low power consumption, and high-speed operation (>100 GHz). The presented high-performance photodetection scheme represents a significant step toward realizing integrated on-chip communication and manifests a new paradigm for developing miniaturized optoelectronics components.

Study of the temperature distribution in Si nanowires under microscopic laser beam excitation

“…The optical absorption by NWs is a critical issue for the calculation of the laser induced heating. Because the NW diameter is smaller than the laser wavelength, the power absorbed by the NWs is diameter dependent [18,35,38,39]. As a consequence of this, significant differences with the bulk absorption take place.…”

Tuning Light Absorption in Core/Shell Silicon Nanowire Photovoltaic Devices through Morphological Design

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] For example, the optical properties of arrays of nano-and microscale wires have been exploited for enhanced light absorption in photovoltaic devices, [16][17][18][19] however, the ability to substantially manipulate absorption in individual nanoscale structures has not been well established. In order to quantify optical resonances supported in individual NWs, scattering [20][21][22] and absorption cross-sections 5,6,11,[23][24][25][26] have been measured or calculated.…”

“…11 Several reports of relative EQE values have been reported for Si and Ge nanowire devices acting as photodetectors. 5,24,25 Our integrated approach to understanding the role of morphology on light absorption in individual p/i/n Si NWs is illustrated in Figure 1. First, we synthesized core/shell p/i/n Si NWs of various sizes and cross-sectional morphologies through tuning of chemical vapor deposition (CVD) growth parameters, as illustrated in Figure 1A.…”

Nanoplasmonics and its Applied Devices

“…They use optical radiation at subwavelength scale. Optical antennas can be used to enhance the efficiency of photodetection [75,76], light emission [77,78], sensing [79], heat transfer [80,81] and spectroscopy [82]. Optical antenna takes care of optical propagation using elements like mirrors, lenses, fibres and diffractive elements while for radiowave and microwave antenna deals with electromagnetic fields at subwavelength scale.…”