An 850 nm monolithically integrated optical receiver front end has been developed with 0.5 μm GaAs PHEMT process, mesa process and interconnected photolithography technology between mesa and plane, which comprises a ...
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An 850 nm monolithically integrated optical receiver front end has been developed with 0.5 μm GaAs PHEMT process, mesa process and interconnected photolithography technology between mesa and plane, which comprises a metal-semiconductor-metal (MSM) photodetector and a transimpedance preamplifier. The photodetector has a photosensitive area and a capacitance of 2000 μm2 and 0.15 pF respectively, as well as a dark current of less than 14 nA under a bias of 4 V. The transimpedance preamplifier has a -3 dB bandwidth close to 10 GHz, with a transimpedance of 43 dBΩ;The front end has a relatively clear output eye diagram for the 850 nm optical signal modulated by 2.5 Gb/s NRZ pseudorandom binary sequence.
We have measured a helicity-dependent photocurrent at zero external magnetic field in a device based on a semiconductor quantum well embedded in a p-i-n junction. The device is excited under vertical incidence with ci...
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We have measured a helicity-dependent photocurrent at zero external magnetic field in a device based on a semiconductor quantum well embedded in a p-i-n junction. The device is excited under vertical incidence with circularly polarized light. The spin filtering effect is evidenced in the temperature range 77–300 K owing to a CoFeB/MgO spin filter with out-of-plane magnetization in remanence. The helicity-dependent photocurrent is explored as a function of the temperature and bias. These characteristics are compared with those of a spin photocurrent device with in-plane magnetized CoFeB/MgO spin filter, excited under oblique incidence with circularly polarized light. In contrast to the in-plane spin filter device, the circularly polarized light asymmetry of the photocurrent in the out-of-plane device depends weakly on the external bias. The two devices are sensitive to the spin filtering of either the in-plane (Sx) or out-of-plane (Sz) photogenerated electron spin in the semiconductor quantum well. The helicity-dependent photocurrent results can be explained by the Dyakonov-Perel electron spin-relaxation mechanism. Our study reveals the giant spin relaxation anisotropy in III-V zinc-blende quantum wells in the presence of a vertical electric field.
Two-dimensional (2D) semiconductors are widely recognized as attractive channel materials for low-power electronics. However, an unresolved challenge is the integration of high-quality, ultrathin high-κ dielectrics t...
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