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2016 Compound Semiconductor Week (CSW) [Includes 28th International Conference on Indium Phosphide & Related Materials (IPRM) & 43rd International Symposium on Compound Semiconductors (ISCS)
The thin film ZLAST(ZnxPbySbzAgmTen) was studied by combinatorial approach. ZLAST thin films were co-deposited from a stoichiometric Ag, Sb, PbTe, and Zn4Sb3 alloy target onto glass substrates using a custom designed radio-frequency (RF) magnetron sputtering system. The crystalline phase and variations in the composition of the thin films were determined using field emission scanning electron microscopy,...
We have successfully mitigated the out-diffusion of Ge during molecular beam epitaxy of InGaAs on Ge by using a GaAsSb layer as evidenced by secondary ion mass spectroscopy. Compared to GaAs, this GaAsSb layer also provides a smoother surface morphology with its root mean square roughness of 0.664 nm. Using a GaAsSb step-graded buffer (SGB) and an AlGaAsSb high resistivity buffer, we are able to grow...
A spin metal-oxide-semiconductor field-effect transistor (MOSFET) is one of the most promising devices for future electronics because of the compatibility with the conventional semiconductor technologies and its variety of potential applications such as reconfigurable circuits; however, there are some problems to be solved to realize spin MOSFET. In particular, realizing and controlling the spin dependent...
In this work, we fabricate Pt, Ni and Pd vertical Schottky barrier diodes (SBDs) on bulk (−201) α-Ga2O3 substrates. We fabricate the diodes on two types of Ga2O3 substrates, un-intentionally doped (UID) with 1017 cm−3 electron concentration and Sn-doped with 5×1018 cm−3 electron concentration. We characterize the diodes with current-voltage (I–V), capacitance-voltage (C-V) and reverse breakdown measurements...
In this work, we characterize the scalability of ZnO TFTs for RF transistor and DC switching applications through variations in channel length, total device periphery, and parasitic gate overlap capacitance. For simple device test structures that have not been optimized for either RF transistors or DC switches, we show drain current density (IDS) and Ron scalability for channel lengths (LC) from 10...
We study local-strained structures of CVD-grown monolayer MoS2 flakes fixed on PMMA. Wrinkle structures are observed on the flakes which are slightly deformed due to compression induced by surrounding PMMA. Moreover, using AFM nanoindentation, we fabricate strained dip structures with different loading force and demonstrate tunability of the dip configuration, hence local strain tunability. Additionally,...
An E-mode GaN MIS-HEMTs using multilayer La2O3/HfO2 as gate insulator is investigated for high power application. The multilayer La2O3/HfO2 composite oxide transformed to HfLaOx amorphous phase with low density of interface traps and border traps after post deposition annealing (PDA) at 6000C as judged from the C-V characteristics of the HfLaOx/GaN MOSCAP. The device exhibits a low ON-resistance of...
Here, we present our recent highlights on monolithically integrated GaAs-nanowire lasers on silicon and further demonstrate capabilities in epitaxial gain control to tune threshold power density and lasing wavelength. Importantly, the investigated NW lasers reveal high spontaneous emission coupling factors (beta-factor) of 0.2, and ultrafast temporal emission down to < 3 ps, equivalent to repetition...
The GaN HEMT power device with field plate for device reliability improvement is investigated. Overall, the field plate structure smooths the electrical field distribution in the HEMT structure and reduces the generation of defects and the interface traps in the device, resulting in higher device breakdown voltage, lower leakage current, and less current degradation with steady dynamic on-resistance...
We fabricated InGaAs-HEMTs with two-step recess (TSR) gates and SiCN-based multi-step slant field plates (FPs). The results indicate that the FP enhances the breakdown voltage (BV) of the TSR gate devices, and the TSR gate improves the current gain cutoff frequency (fT) in comparison with the conventional recess gate devices with FPs. The results also indicate that the TSR gate makes BV lower than...
We investigate fabrication of a photonic-crystal structure by air-hole retained crystal regrowth using TBAs-based MOVPE for GaAs based photonic-crystal lasers. Air holes having a filling factor of 10 % (the depth was 250 nm and the width was 110 nm) are successfully embedded. The embedded air holes show characteristic shapes due to anisotropy of growth rate along different crystal planes, such as...
Nonpolar AlGaN light-emitting diodes have been attracting much attention due to their potential for realizing optoelectronic devices with high efficiency and stability. However, few studies have been reported on the optical properties of nonpolar AlGaN quantum wells (QWs) on sapphire because of the difficulty in the growth. Here, we report the fabrication of an a-plane AlGaN QW on r-plane sapphire...
Electrically driven CW operation of energy-efficient ultra-compact InP-based nanolasers in a Silicon photonic platform is demonstrated. The nanolaser diode is single mode and emits at 1560 nm with SMSR grater than 20dB. The threshold is low, around 0.1mA at 1 V and the emitted power in the SOI waveguide is of the order of 0.1mW giving a wall-plug efficiency higher than 10 percents.
In situ synchrotron X-ray diffraction studies during the growth of arsenide and nitride semiconductors are presented. The large penetration depth of X-rays was exploited for revealing structural changes at buried interfaces as well as near the surface. Experiments were performed at a synchrotron beamline, BL11XU, SPring-8, using a molecular-beam epitaxy chamber integrated with a high-precision X-ray...
We show high-temperature ferromagnetism in heavily Fe-doped ferromagnetic semiconductor (Ga1−x,Fex)Sb (x = 23% and 25%) thin films grown by low-temperature molecular beam epitaxy (LT-MBE). Our crystal structure analysis by scanning transmission electron microscopy (STEM) indicates that the (Ga1−x,Fex)Sb thin films maintain the zinc-blende crystal structure at x = 25%. The intrinsic ferromagnetism...
Spin-coated Ag nanoparticles on a plasma-treated p-GaN layer applied for the light extraction of near-ultraviolet light-emitting diode (NUV-LED) have been demonstrated. The ITO/nano-Ag window can form a plasmonic window, where the Ar plasma treatment can improve the uniformity of the Ag nanoparticle distribution. By applying this technique for surface-plasmon-enhanced NUV-LED, the output power (@350...
In the case of III–V dilute magnetic semiconductors (DMSs), the holes from Mn doping are known to mediate the ferromagnetic interaction. We firstly demonstrated the organic molecular manipulation of the magnetism of (Ga,Mn)As. Mn-doped GaAs thin films with various thicknesses were grown by low-temperature molecular-beam epitaxy, and organic charge-transfer molecules were deposited on the surface of...
III-nitride semiconductor based heterojunction field effect transistors (HFETs) with metal insulator semiconductor (MIS) structure have attracted much attention as power semiconductor devices that enable low-loss and high-power driving. Amorphous alumina (Al2O3) was deposited by atomic layer deposition (ALD), which has appropriate physical properties as gate dielectric in MIS-HFETs, such as high relative...
We have investigated the Schottky barrier diode (SBD) and device (DC and pulsed I–V) characteristics of AlGaN/GaN HEMTs fabricated with sputtered TiN Schottky gate. The measured Schottky barrier height (SBH) of TiN on Al0.26Ga0.74N/GaN HEMT structure are 1.126 and 1.105 eV by I–V and I-V-T measurements, respectively. No hysteresis is observed in between forward and reverse C-V sweeps of TiN SBD. Compared...
We provide a perspective on the emergence of “topological spintronics,” which exploits the helical spin texture of 2D surface states in 3D topological insulators. Spin- and angle-resolved photoemission spectroscopy shows how this spin texture can be engineered using quantum tunneling between surfaces [1], while spin transport devices enable electrical measurements of the spin-momentum “locking” [2,3]...
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