Superior optical (λ ∼ 1550 nm) emission and detection characteristics of Ge microdisks grown on virtual Si_0.5Ge_0.5/Si substrates using molecular beam epitaxy

Abstract

We report the optical characteristics of relatively large sized (∼7.0-8.0 μm) but low aspect ratio Ge microdisks grown on a virtual Si 0.5 Ge 0.5 substrate using molecular beam epitaxy following the Stranski-Krastanov growth mechanism. Grown microdisks with very low aspect ratio Ge islands exhibit direct band gap (∼0.8 eV) photoluminescence emission sustainable up to room temperature, enabled by the confinement of carriers into the microdisks. p-i-n diodes with an intrinsic layer containing Ge microdisks have been fabricated to study their emission and photoresponse characteristics at an optical communication wavelength of ∼1550 nm. A strong electroluminescence at 1550 nm has been achieved at low temperatures in the device for a very low threshold current density of 2.56 μA cm −2 due to the strong confinement of injected holes. The emission characteristics of the fabricated device with respect to the injected current density and temperature have been studied. Novel emission and optical modulation characteristics at 1550 nm of the fabricated p-i-n device containing Ge microdisks grown on a virtual SiGe substrate indicate its potential for Si CMOS compatible on-chip optical communications.

SiGe nanocrystals in SiO2 with high photosensitivity from visible to short-wave infrared

“…SiO 2 is the most suitable matrix because of its compatibility with the CMOS technology and because it forms the best interface with Si substrate. These efforts are made with the purpose of improving the optoelectronic devices on Si and enabling the SiGe NCs integration in a large area of applications such as non-volatile memories [18][19][20] , GeSi based high-mobility transistors 21 , photo-MOSFETs 22 , solar cells [23][24][25] , thermoelectric applications 26 and high-performance photodetectors 7,[27][28][29][30] .…”

Size-tunable electroluminescence characteristics of quantum confined Si nanocrystals embedded in Si-rich oxide matrix

“…A great deal of research effort has been dedicated to develop CMOS compatible optical sources on Si platforms replacing hybrid systems based on GaN, GaAs, and Ge on Si. [1][2][3][4] Reducing the dimensions of Si structures below the excitonic Bohr radius of Si ($4.8 nm) results in light emission due to the quantum confinement effect (QCE). [5][6][7][8] Different approaches of light emission through the QCE have been reported to date based on Si nanowires, [9][10][11][12] nanocones, 13,14 colloidal nanocrystals, 15,16 and nanocrystals in the oxide matrix.…”

Low-noise, high-detectivity, polarization-sensitive, room-temperature infrared photodetectors based on Ge quantum dot-decorated Si-on-insulator nanowire field-effect transistors

“…High-performance infrared (IR) photodetectors have potential applications in fiber optic communications, on-chip optical interconnects, night vision imaging, remote sensing and environmental monitoring [1][2][3]. IR detection over a range of different wavelengths is currently driven by solid-state detectors using thin films and nanostructures including quantum wells/dots of narrow band gap materials like Ge, InGaAs, HgCdTe, PbSe etc [4][5][6][7][8][9][10]. However, the greatest challenge is to realize the monolithic integration of detector arrays with planar metal oxide silicon (CMOS) technology nodes below 28 nm [4,5].…”