P. D. Ye

Purdue University, ウェストラファイエット, Indiana, United States

Are you P. D. Ye?

Claim your profile

Publications (242)647.5 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The interfacial chemistry between the “half cycle” atomic layer deposited (ALD) Al2O3 and black phosphorus (black-P) was examined using in situ X-ray photoelectron spectroscopy (XPS). Two samples, native and freshly exfoliated, are investigated to understand the effect of oxidation on the initial ALD nucleation. It is found that annealing samples in the ALD chamber results in an increase of oxidation, caused most likely by oxygen transferring from surface adventitious contamination. After the half cycle ALD process, the P-oxide concentration increases, indicating interface deterioration during the Al2O3 deposition. Based on the Al2O3 nucleation or growth behavior observed in the half cycle ALD studies, a true ALD growth tends to occur only after formation of a complete monolayer of oxide on the clean black-P surface with minimum oxidation concentration.
    Microelectronic Engineering 11/2015; 147. DOI:10.1016/j.mee.2015.04.014 · 1.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: 2D transition metal dichalcogenides (TMDCs) are nanomanufactured using a generalized strategy with self-assembled DNA nanotubes. DNA nanotubes of various lengths serve as lithographic etch masks for the dry etching of TMDCs. The nanostructured TMDCs are studied by atomic force microscopy, photoluminescence, and Raman spectroscopy. This parallel approach can be used to manufacture 2D TMDC nanostructures of arbitrary geometries with molecular-scale precision. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
    Small 08/2015; DOI:10.1002/smll.201501431 · 8.37 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In situ "half cycle" atomic layer deposition (ALD) of Al2O3 was carried out on black phosphorus ("black-P") surfaces with intentionally modifying the phosphorus oxide concentrations. X-ray photoelectron spectroscopy is employed to investigate the interfacial chemistry and the nucleation of the Al2O3 on black-P surfaces. This work suggests that exposing a sample that is initially free of phosphorus oxide to the ALD precursors does not result in detectable oxidation. However, when the phosphorus oxide is formed on the surface prior to deposition, the black-P can react with both the surface adventitious oxygen contamination and the H2O precursor at the deposition temperature of 200 C. As a result, the concentration of the phosphorus oxide increases after both annealing and the atomic layer deposition process. The nucleation rate of Al2O3 on black-P is correlated with the amount of oxygen on samples prior to the deposition. The growth of Al2O3 follows a "substrate inhibited growth" behavior where an incubation period is required. Ex situ atomic force microscopy is also used to investigate the deposited Al2O3 morphologies on black-P where the Al2O3 tends to form islands on the exfoliated black-P samples. Therefore, surface functionalization may be needed to get a conformal coverage of Al2O3 on the phosphorus oxide free samples.
    ACS Applied Materials & Interfaces 05/2015; 7(23). DOI:10.1021/acsami.5b03192 · 6.72 Impact Factor
  • M. Si · S. Shin · N.J. Conrad · J. Gu · J. Zhang · M.A. Alam · P.D. Ye ·
    [Show abstract] [Hide abstract]
    ABSTRACT: InGaAs is a promising channel material for high performance CMOS logic circuits due to its large electron injection velocity. InGaAs Gate-All-Around (GAA) MOSFETs have been demonstrated; these transistors offer large drive current and excellent immunity to short channel effects (SCE). However, the characterization and reliability of InGaAs GAA MOSFETs are still challenging. In this paper, we (i) discuss the challenges and new characterization methodologies to evaluate Dit, Rsd and other parameters on short channel InGaAs GAA MOSFETs, (ii) discuss device characterization based on low frequency noise and RTN, (iii) image the complexity of heat dissipation by using newly developed thermoreflectance method, and (iv) review the current research on 3D InGaAs MOSFET reliability including PBTI, HCI, and gate dielectric breakdown.
  • Heng Wu · Mengwei Si · Lin Dong · Jiangjiang Gu · Jingyun Zhang · Peide D. Ye ·
    [Show abstract] [Hide abstract]
    ABSTRACT: A novel recessed channel and source/drain (S/D) technique is employed in Ge nMOSFETs, which greatly improves metal contacts to n-type Ge with contact resistance of down to 0.23 $Omega cdot {rm mm}$ and enhances gate electrostatic control with $I_{rm ON} / I_{rm OFF}$ of $> 10^{5}$ . The recessed S/D contacts are thoroughly investigated, showing strong dependence on the doping profile. For the first time, the drain current of Ge nMOSFETs has exceeded 1 A/mm with an $I_{d}$ of 1043 mA/mm on a 40-nm $L_{rm ch}$ device. Scalability study is carried out in deep sub-100-nm region on Ge nMOSFETs with $L_{rm ch}$ down to 25 nm. Interface study is also conducted with a new postoxidation method introduced, which significantly reduces the interface trap density. Device behaviors corresponding to interface traps are also investigated through a Technology Computer Aided Design simulation.
    IEEE Transactions on Electron Devices 05/2015; 62(5):1419-1426. DOI:10.1109/TED.2015.2412878 · 2.47 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: High-performance 0.1- $mu text{m}$ InAlN/GaN high electron-mobility transistors (HEMTs) have been successfully developed for power amplifiers operating at E-band (targeting 71–76 and 81–86-GHz bands). High maximum drain current of 1.75 A/mm and maximum extrinsic transconductance of 0.8 S/mm have been achieved for depletion-mode devices. Enhancement-mode HEMTs have also shown maximum drain current of 1.5 A/mm and maximum extrinsic transconductance of 1 S/mm. The selection of atomic layer deposition aluminum oxide (Al2O3) for device passivation enables a two-terminal breakdown voltage of $sim 25$ V, excellent subthreshold characteristics as well as the pulsed-IV featuring little current collapse for both types of HEMTs. When biased at a drain voltage of 10 V, a first-pass two-stage power amplifier design based on 0.1- $mu text{m}$ depletion-mode devices has demonstrated an output power of 1.43 W with 12.7% power-added efficiency at 86 GHz, a level of performance that has been attained previously only by state-of-the-art counterparts based on AlGaN/GaN HEMTs at a much higher drain bias and compression level.
    IEEE Electron Device Letters 05/2015; 36(5):442-444. DOI:10.1109/LED.2015.2409264 · 2.75 Impact Factor
  • Source
    Yexin Deng · Nathan J. Conrad · Zhe Luo · Han Liu · Xianfan Xu · Peide D. Ye ·
    [Show abstract] [Hide abstract]
    ABSTRACT: The metal contacts on 2D black phosphorus field-effect transistor and photodetectors are studied. The metal work functions can significantly impact the Schottky barrier at the metal-semiconductor contact in black phosphorus devices. Higher metal work functions lead to larger output hole currents in p-type transistors, while ambipolar characteristics can be observed with lower work function metals. Photodetectors with record high photoresponsivity (223 mA/W) are demonstrated on black phosphorus through contact-engineering.
    Electron Devices Meeting, 1988. IEDM '88. Technical Digest., International 03/2015; 2015. DOI:10.1109/IEDM.2014.7046987
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Black phosphorus has been revisited recently as a new two-dimensional material showing potential applications in electronics and optoelectronics. Here we report, for the first time, the anisotropic in-plane thermal conductivity of suspended few-layer black phosphorus measured by micro-Raman spectroscopy. The armchair and zigzag thermal conductivities ($k_{armchair}$ and $k_{zigzag}$) are ~20 W/mK and ~40 W/mK for black phosphorus films thicker than 15 nm, respectively, and decrease to ~10 W/mK and ~20 W/mK as the film thickness is reduced, exhibiting significant anisotropy of in-plane thermal transport and strong surface scattering of acoustic phonons. The thermal conductivity anisotropic ratio $k_{zigzag}/k_{armchair}$ is found to be ~2 for thick black phosphorus films and drops to ~1.5 for the thinnest 9.5-nm-thick film. First-principles modeling of few-layer black phosphorus reveals that the observed anisotropy is primarily related to the asymmetric phonon dispersion, whereas the intrinsic phonon scattering rates are found to be similar along the armchair and zigzag directions. Surface scattering in the black phosphorus films is shown to strongly suppress the contribution of long-mean-free-path acoustic phonons.
    Nature Communications 03/2015; 6. DOI:10.1038/ncomms9572 · 11.47 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Thermal characterization of high-speed switching power transistors, such as high electron mobility transistors (HEMT), is critical for the evaluation of their performance as well as their long-term reliability. Unlike IR thermal imaging, thermoreflectance thermal imaging (TRI) uses LED lights in the visible range and therefore can be used to measure thermal response of these nanoscale devices under operating condition. However, TRI is also limited in terms of spatial resolution by optical diffraction as we reach device sizes on the order of hundreds of nanometer. We carried out a series of thermoreflectance thermal imaging experiments on the metal heater lines with widths ranging from 100 nm to 1 µm fabricated on InGaAs semiconductor film. Analytical and finite element numerical modeling are used to compare experimental data with theoretical temperature profiles. We demonstrate that thermoreflectance thermal imaging is capable of detecting temperature rise in devices with sub-diffraction feature sizes. We show that optical diffraction leads to underestimation of the magnitude of small scale hot spots. We also present a combined analytical-numerical model to reproduce the experimental results, and finally propose an approach that can be utilized to compensate for this diffraction artifact and acquire the correct temperature response from thermoreflectance thermal imaging results.
    IEEE SemiTherm 2015, Santa Clara, CA; 03/2015
  • N. Conrad · M. Si · S.H. Shin · J.J. Gu · J. Zhang · M.A. Alam · P.D. Ye ·
    [Show abstract] [Hide abstract]
    ABSTRACT: In this work, we report the first observation of RTN in highly scaled InGaAs GAA MOSFETs fabricated by a top-down approach. RTN and low frequency noise were systematically studied for devices with various gate dielectrics, channel lengths and nanowire diameters. Mobility fluctuation is confirmed to be the source of low-frequency noise, showing 1/f characteristics. Low-frequency noise was found to decrease as the channel length scaled down from 80 nm to 20 nm, indicating the near-ballistic transport in highly scaled InGaAs GAA MOSFET.
  • H. Wu · N. Conrad · W. Luo · P.D. Ye ·
    [Show abstract] [Hide abstract]
    ABSTRACT: We report the first experimental demonstration of Ge CMOS circuits, based on a novel recessed channel and S/D technique. Aggressively scaled non-Si CMOS logic devices with channel lengths (Lch) from 500 to 20 nm, channel thicknesses (Tch) of 25 and 15 nm, EOTs of 4.5 and 3 nm and a small width ratio (Wn:Wp=1.2) are realized on a Ge-on-insulator (GeOI) substrate. The CMOS inverters have high voltage gain of up to 36 V/V, which is the best value among all of the non-Si CMOS results by the standard top-down approach. Scalability studies on Ge CMOS inverters down to 20 nm are carried out for the first time. NAND and NOR logic gates are also investigated.
    Electron Devices Meeting, 1988. IEDM '88. Technical Digest., International 02/2015; 2015:9.3.1-9.3.4. DOI:10.1109/IEDM.2014.7047016
  • [Show abstract] [Hide abstract]
    ABSTRACT: Gate-all-around MOSFETs use multiple nanowires to achieve target ION, along with excellent 3D electrostatic control of the channel. Although self-heating effect (SHE) has been a persistent concern, the existing characterization methods, based on indirect measure of mobility and specialized test structures, do not offer adequate spatio-temporal resolution. In this paper, we develop an ultra-fast, high resolution thermo-reflectance (TR) imaging technique to (i) directly observe the increase in local surface temperature of the GAA-FET with different number of nanowires (NWs), (ii) characterize/interpret the time constants of heating and cooling through high resolution transient measurements, (iii) identify critical paths for heat dissipation, and (iv) detect in-situ time-dependent breakdown of individual NW. Our approach also allows indirect imaging of quasi-ballistic transport and corresponding drain/source asymmetry of self-heating. Combined with the complementary approaches that probe the internal temperature of the NW, the TR-images offer a high resolution map of self-heating in the surround-gate devices with unprecedented precision, necessary for validation of electro-thermal models and optimization of devices and circuits.
    Electron Devices Meeting, 1988. IEDM '88. Technical Digest., International 02/2015; 2015(11):20.3.1-20.3.4. DOI:10.1109/IEDM.2014.7047088
  • [Show abstract] [Hide abstract]
    ABSTRACT: Inversion-mode GaAs wave-shaped metal-oxide-semiconductor field-effect transistors (WaveFETs) are demonstrated using atomic-layer epitaxy of La2O3 as gate dielectric on (111)A nano-facets formed on a GaAs (100) substrate. The wave-shaped nano-facets, which are desirable for the device on-state and off-state performance, are realized by lithographic patterning and anisotropic wet etching with optimized geometry. A well-behaved 1 μm gate length GaAs WaveFET shows a maximum drain current of 64 mA/mm, a subthreshold swing of 135 mV/dec, and an ION/IOFF ratio of greater than 107.
    Applied Physics Letters 02/2015; 106(7):073506. DOI:10.1063/1.4913431 · 3.30 Impact Factor
  • Woongsik Nam · James I Mitchell · Peide D Ye · Xianfan Xu ·
    [Show abstract] [Hide abstract]
    ABSTRACT: We demonstrate a single-step, laser-based technique to fabricate silicon nanowire field effect transistors. Boron-doped silicon nanowires are synthesized using a laser-direct-write chemical vapor deposition process, which can produce nanowires as small as 60 nm, far below the diffraction limit of the laser wavelength of 395 nm. In addition, the method has the advantages of in situ doping, catalyst-free growth, and precise control of nanowire position, orientation, and length. Silicon nanowires are directly fabricated on an insulating surface and ready for subsequent device fabrication without the need for transfer and alignment, thus greatly simplifying device fabrication processes. Schottky barrier nanowire field effect transistors with a back-gate configuration are fabricated from the laser-direct-written Si nanowires and electrically characterized.
    Nanotechnology 02/2015; 26(5):055306. DOI:10.1088/0957-4484/26/5/055306 · 3.82 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: High performance-scaled MoS2 transistors down to 100 nm are studied at various temperatures down to 20 K, where highest drive current of 800 μA μm(-1) can be achieved. Extremely low electrical noise of 2.8 × 10(-10) μm(2) Hz(-1) at 10 Hz is also achieved at room temperature. Furthermore, negative differential resistance behavior is experimentally observed and its origin of self-heating is identified using pulsed-current-voltage measurements. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
    Advanced Materials 01/2015; 27(9). DOI:10.1002/adma.201405068 · 17.49 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we report the observation of random telegraph noise (RTN) in highly scaled InGaAs gate-all-around (GAA) MOSFETs fabricated by a top-down approach. RTN and low-frequency noise were systematically studied for devices with various gate dielectrics, channel lengths, and nanowire diameters. Mobility fluctuation is identified to be the source of 1/f noise. The 1/f noise was found to decrease as the channel length scaled down from 80 to 20 nm comparing with classical theory, indicating the near-ballistic transport in highly scaled InGaAs GAA MOSFET. Low-frequency noise in ballistic transistors is discussed theoretically.
    IEEE Transactions on Electron Devices 01/2015; DOI:10.1109/TED.2015.2433921 · 2.47 Impact Factor
  • Source
    Yuchen Du · Lingming Yang · Han Liu · Peide D. Ye ·
    [Show abstract] [Hide abstract]
    ABSTRACT: Layered two-dimensional (2D) semiconducting transition metal dichalcogenides (TMD) have been widely isolated, synthesized, and characterized recently. Numerous 2D materials are identified as the potential candidates as channel materials for future thin film technology due to their high mobility and the exhibiting bandgaps. While many TMD filed-effect transistors (FETs) have been widely demonstrated along with a significant progress to clearly understand the device physics, large contact resistance at metal/semiconductor interface still remain a challenge. From 2D device research point of view, how to minimize the Schottky barrier effects on contacts thus reduce the contact resistance of metals on 2D materials is very critical for the further development of the field. Here, we present a review of contact research on molybdenum disulfide and other TMD FETs from the fundamental understanding of metal-semiconductor interfaces on 2D materials. A clear contact research strategy on 2D semiconducting materials is developed for future high-performance 2D FETs with aggressively scaled dimensions.
    APL Materials 10/2014; 2(9). DOI:10.1063/1.4894198 · 2.79 Impact Factor
  • Source
    Han Liu · Yuchen Du · Yexin Deng · Peide D. Ye ·
    [Show abstract] [Hide abstract]
    ABSTRACT: Phosphorus is one of the most abundant elements preserved in earth, and it comprises a fraction of 0.1% of the earth crust. In general, phosphorus has several allotropes, and the two most commonly seen allotropes, i.e. white and red phosphorus, are widely used in explosives and safety matches. In addition, black phosphorus, though rarely mentioned, is a layered semiconductor and has great potential in optical and electronic applications. Remarkably, this layered material can be reduced to one single atomic layer in the vertical direction owing to the van der Waals structure, and is known as phosphorene, in which the physical properties can be tremendously different from its bulk counterpart. In this review article, we trace back to the research history on black phosphorus of over 100 years from the synthesis to material properties, and extend the topic from black phosphorus to phosphorene. The physical and transport properties are highlighted for further applications in electronic and optoelectronics devices.
    Chemical Society Reviews 10/2014; 44(9). DOI:10.1039/C4CS00257A · 33.38 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Low-resistivity metal-semiconductor (M-S) contact is one of the urgent challenges in the research of 2D transition metal dichalcogenides (TMDs). Here, we report a chloride molecular doping technique which greatly reduces the contact resistance (Rc) in the few-layer WS2 and MoS2. After doping, the Rc of WS2 and MoS2 have been decreased to 0.7 kohm*um and 0.5 kohm*um, respectively. The significant reduction of the Rc is attributed to the achieved high electron doping density thus significant reduction of Schottky barrier width. As a proof-ofconcept, high-performance few-layer WS2 field-effect transistors (FETs) are demonstrated, exhibiting a high drain current of 380 uA/um, an on/off ratio of 4*106, and a peak field-effect mobility of 60 cm2/V*s. This doping technique provides a highly viable route to diminish the Rc in TMDs, paving the way for high-performance 2D nano-electronic devices.
    Nano Letters 10/2014; 14(11). DOI:10.1021/nl502603d · 13.59 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This letter evaluates temporal and thermal stability of a state-of-the-art few-layer phosphorene MOSFET with Al2O3 surface passivation and Ti/Au top gate. As fabricated, the phosphorene MOSFET was stable in atmosphere for at least 100 h. With annealing at 200{\deg}C in dry nitrogen for 1 h, its drain current increased by an order of magnitude to approximately 100 mA/mm, which could be attributed to the reduction of trapped charge in Al2O3 and/or Schottky barrier at the source and drain contacts. Thereafter, the drain current was stable between -50{\deg}C and 150{\deg}C up to at least 1000 h. These promising results suggest that environmental protection of phosphorene should not be a major concern, and passivation of phosphorene should focus on its effect on electronic control and transport as in conventional silicon MOSFETs. With cutoff frequencies approaching the gigahertz range, the present phosphorene MOSFET, although far from being optimized, can meet the frequency and stability requirements of most flexible electronics for which phosphorene is intrinsically advantageous due to its corrugated lattice structure.
    IEEE Electron Device Letters 10/2014; 35(12). DOI:10.1109/LED.2014.2362841 · 2.75 Impact Factor

Publication Stats

5k Citations
647.50 Total Impact Points


  • 2005-2015
    • Purdue University
      • • School of Electrical and Computer Engineering
      • • Department of Electrical and Computer Engineering Technology (ECET)
      ウェストラファイエット, Indiana, United States
    • Lehigh University
      Bethlehem, Pennsylvania, United States
  • 2014
    • Michigan State University
      • Department of Physics and Astronomy
      Ист-Лансинг, Michigan, United States
  • 2012
    • Center for Responsible Nanotechnology
      Menlo Park, California, United States
  • 2001-2006
    • Princeton University
      • Department of Electrical Engineering
      Princeton, New Jersey, United States
  • 2002-2004
    • Florida State University
      • Department of Physics
      Tallahassee, Florida, United States
    • National High Magnetic Field Laboratory
      Tallahassee, Florida, United States