High-frequency microwave noise characteristics of InAlN/GaN high-electron mobility transistors on Si (111) substrate

A stress engineered three dimensional (3D) Triple T-gate (TT-gate) on lattice matched In 0.17 Al 0.83 N/GaN nano-channel (NC) Fin-High-Electron-Mobility Transistor (Fin-HEMT) with significantly enhanced device performance was achieved that is promising for high-speed device applications. The Fin-HEMT with 200-nm effective fin-width (W eff ) exhibited a very high I Dmax of 3940 mA/mm and a highest g m of 1417 mS/mm. This dramatic increase of I D and g m in the 3D TTgate In 0.17 Al 0.83 N/GaN NC Fin-HEMT translated to an extracted highest electron velocity (v e ) of 6.0 Â 10 7 cm/s, which is $1.89Â higher than that of the conventional In 0.17 Al 0.83 N/GaN HEMT (3.17 Â 10 7 cm/s). The v e in the conventional III-nitride transistors are typically limited by highly efficient optical-phonon emission. However, the unusually high v e at 300 K in the 3D TT-gate In 0.17 Al 0.83 N/GaN NC Fin-HEMT is attributed to the increase of in-plane tensile stress component by SiN passivation in the formed NC which is also verified by micro-photoluminescence (0.47 6 0.02 GPa) and micro-Raman spectroscopy (0.39 6 0.12 GPa) measurements. The ability to reach the v e ¼ 6 Â 10 7 cm/s at 300 K by a stress engineered 3D TT-gate lattice-matched In 0.17 Al 0.83 N/GaN NC Fin-HEMTs shows they are promising for next-generation ultra-scaled highspeed device applications. V

InP-based uni-traveling-carrier photodiodes (UTC-PDs) with novel dipole-doped structure to achieve high photocurrent as well as wide bandwidth are demonstrated in this work. The dipole-doped layers in combination with a 22-nm-thick undoped InGaAs setback layer were employed at the InGaAs/InP absorption and collection interface to reduce the current blocking effect. A high photocurrent of 160 mA with 1.9 GHz 3-dB bandwidth from a 70-µm -diameter top-illuminated UTC-PD is achieved. A large 3-dB bandwidth of 62.5GHz, which is estimated with an equivalent circuit model, has also been obtained from a 12-µm -diameter UTC-PD device. The results demonstrate that the dipole-doping can serve as an effective alternative to the quaternary InGaAsP layer at InGaAs/InP interface for InP-based UTC-PD to suppress the current blocking and reduce the complexity in epi-layers growth and device fabrication. Index Terms-Dipole-doped layer, high speed, photocurrent, uni-traveling-carrier photodiodes (UTC-PDs), 3-dB bandwidth. I. INTRODUCTIONIGH-photocurrent and high-speed photodiodes (PDs) have attracted intensive research interests for the application of CATV network, photonic analog-to-digital converter and optical links to phased array antenna [1,2]. To meet the requirements for both high photocurrent and high speed operation, various types of photodiodes have been investigated. Conventional PIN-PD [3] is one of the simplest PD structures which is used for a wide range of applications. In a conventional PIN-PD structure, both electrons and holes are photo-generated in the depletion layer. The holes with much lower drift mobility and velocity, contribute dominantly to the space charge and can result in the degradation of device performance, especially under high power illumination [1].Hence, Ishibashi et al. [1] proposed a new type of photodiode -uni-traveling-carrier photodiode (UTC-PD) which could

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Non-Gaussian operations on two mode squeezed vacuum states (TMSV) in continuous variable measurement device independent quantum key distribution (CV-MDI-QKD) protocols have been shown to effectively increase the total transmission distances drastically. In this paper we show that photon subtraction on a two mode squeezed coherent (PSTMSC) state can further improve the transmission distances remarkably. To that end we also provide a generalized covariance matrix corresponding to PSTMSC, which has not been attempted before. We show that coherence, defined as the amount of displacement of vacuum state, along with non-Gaussianity can help improve the performance of prevalent CV-MDI-QKD protocols. Furthermore, since we use realistic parameters, our technique is experimentally feasible and can be readily implemented. * chandankumar@iisermohali.ac.in † jaskaransinghnirankari@iisermohali.ac.in ‡ soumyabose@iisermohali.ac.in § arvind@iisermohali.ac.in