Tensile strained Ge p-i-n photodetectors on Si platform for C and L band telecommunications

Abstract

We demonstrate a 0.25% tensile strained Ge p-i-n photodetector on Si platform that effectively covers both C and L bands in telecommunications. The direct band edge of the Ge film has been pushed from 1550 to 1623 nm with 0.25% tensile strain, enabling effective photon detection in the whole L band. The responsivities of the device at 1310, 1550, and 1620 nm are 600, 520, and 100mA∕W under 0 V bias, which can be further improved to 980, 810, and 150mA∕W with antireflection coating based on calculations. Therefore, the device covers the whole wavelength range used in telecommunications. The responsivities at 1310 and 1550 nm are comparable to InGaAs photodetectors currently used in telecommunications. In the spectrum range of 1300–1650 nm, maximum responsivity was already achieved at 0 V bias because carrier transit time is much shorter than carrier recombination life time, leading to ∼100% collection efficiency even at 0 V bias. This is a desirable feature for low voltage operation. The absorption coefficients of 0.25% tensile strained Ge in the L band have been derived to be nearly an order of magnitude higher than bulk Ge. The presented device is compatible with conventional Si processing, which enables monolithic integration with Si circuitry.

Bound-state third-order optical nonlinearities of germanium nanocrystals embedded in a silica host matrix

“…5 Finally, the proximity of direct-gap optical transitions in bulk Ge to the fiber-optic communication wavelength of 1.5 m range is particularly important. This has recently stimulated extensive interest; notably tensile-strained Ge photodetectors on Si platform has been demonstrated 6 and a tensile-strained Ge-based laser is proposed. 7 If the latter can also be experimentally demonstrated, this will mark the dawn of the germanium photonics era.…”

High-speed Ge photodetector monolithically integrated with large cross-section silicon-on-insulator waveguide

“…The Ge length only needs to be 10 m to absorb over 98% of the light as its absorption coefficient is around 4000 cm −1 . 9 This horizontal p-i-n configuration enables a very narrow intrinsic Ge region, hence reducing the a͒ Electronic mail: dfeng@kotura.com. …”

“…This has fueled significant research and development work in this area in the past few years. [1][2][3][4][5][6][7][8][9][10][11] Many silicon-based active photonics components, such as high-speed modulators and Ge photodetectors [4][5][6][7][8][9][10] have been demonstrated on submicron waveguides. However, submicron SOI waveguides still suffer from high fiber coupling loss, high polarization dependent loss, and large waveguide birefringence and phase noise.…”

Surface-enhanced Raman scattering microfluidic sensor

“…One is immobilized silver/gold on the substrate by lithographic techniques which can adsorb with the sample flow and generate the surface Raman signal, and another one depends on the continuous gold/silver particle flow mixing with reagent flow in a controlled manner. Liu 121 and Kho 122 fabricated nanowell-based silver substrates and periodic active nanostructure to get SERS signal. Dluhy 123 used electron beam evaporation to deposit silver arrays.…”