APL Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

3 Dec 2001

Volume 79, Issue 23, pp. 3749-3889

Return to All Sections
back to top
RSS Feeds

Degradation in metal-oxide-semiconductor structure with ultrathin gate oxide due to external compressive stress

Chao-Chi Hong and Jenn-Gwo Hwu

Appl. Phys. Lett. 79, 3797 (2001); http://dx.doi.org/10.1063/1.1420491 (3 pages) | Cited 9 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effect of external stress on metal-oxide-semiconductor (MOS) structure with ultrathin gate oxide (∼1.5 nm) was studied. J–V characteristics of fresh and stressed samples revealed that the tensile stress had little effect on J–V curves, whereas the compressive stress obviously increased the leakage current by about several hundred in percentages with respect to the fresh sample, in both positive and negative gate biases. This increase in leakage current was suggested to be attributed to the increase of interface states and silicon bulk traps under external compressive stress in the MOS device with an inherent tensile stressed silicon. In addition, we also found that once the device was damaged by the previously applied compressive stress, the second applied compressive stress of the same magnitude would not create more damage unless the device was breakdown. © 2001 American Institute of Physics.
Show PACS
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
73.20.At Surface states, band structure, electron density of states

Light-induced increase in the open-circuit voltage of thin-film heterogeneous silicon solar cells

K. Lord, B. Yan, J. Yang, and S. Guha

Appl. Phys. Lett. 79, 3800 (2001); http://dx.doi.org/10.1063/1.1420778 (3 pages) | Cited 17 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We observe a significant light-induced increase in open-circuit voltage, Voc, of solar cells whose intrinsic (i) layer consists of an amorphous and microcrystalline mixed phase. The increase depends on the i-layer thickness and light-soaking intensity. An increase of as large as 150 mV or 20% of the original Voc is observed. The original Voc is restored after subsequent thermal annealing. The possible mechanism for the Voc increase is discussed. © 2001 American Institute of Physics.
Show PACS
84.60.Jt Photoelectric conversion
61.72.Cc Kinetics of defect formation and annealing
72.40.+w Photoconduction and photovoltaic effects

Strain-induced piezoelectric field effects on light emission energy and intensity from AlInGaN/InGaN quantum wells

M. E. Aumer, S. F. LeBoeuf, B. F. Moody, and S. M. Bedair

Appl. Phys. Lett. 79, 3803 (2001); http://dx.doi.org/10.1063/1.1418453 (3 pages) | Cited 15 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on the effects of the piezoelectric field and well width on the transition energy and intensity for InGaN quantum well structures with GaN or AlInGaN quaternary barriers. It was found that the emission energy of compressively strained GaN/In0.08Ga0.92N quantum wells exhibits a strong well width dependence not accounted for by quantum confinement subband energy shifting alone. However, for unstrained quantum well layers with quaternary barriers, no emission energy dependence on width was observed due to the elimination of the piezoelectric field, which was measured to be at least 0.6 MV/cm for the strained quantum wells. Furthermore, the unstrained quantum wells demonstrated a higher intensity than their strained counterparts for all quantum well widths investigated. The current data will help clarify the origin of emission in InGaN quantum wells. © 2001 American Institute of Physics.
Show PACS
78.66.Fd III-V semiconductors
78.55.Cr III-V semiconductors
78.67.De Quantum wells
77.65.Ly Strain-induced piezoelectric fields
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.

Mechanism of photoluminescence in GaN/Al0.2Ga0.8N superlattices

C. H. Chen, H. J. Chang, Y. F. Chen, W. S. Fann, H. X. Jiang, and J. Y. Lin

Appl. Phys. Lett. 79, 3806 (2001); http://dx.doi.org/10.1063/1.1420495 (3 pages) | Cited 2 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present photoluminescence (PL) and time-resolved photoluminescence measurements in GaN/Al0.2Ga0.8N superlattices grown by metalorganic chemical vapor deposition under the optimal GaN-like growth conditions. We found that the carrier confinement of our samples is better than most of the previous reports. The dependence of the PL emission energy and intensity on temperature, in the low temperature regime, is consistent with recombination mechanisms involving localized states attributed to a small degree of interface fluctuations. Picosecond time-resolved photoluminescence spectroscopy has been employed to probe the well-width dependence of the lifetime of these superlattices. We see that the recombination lifetime increases with the decrease of well width. This behavior can be interpreted by the fact that the effect of localization keeping carriers away from nonradiative pathways can be enhanced by a decrease in the well width. This explanation is consistent with the temperature-dependent PL data. © 2001 American Institute of Physics.
Show PACS
78.66.Fd III-V semiconductors
78.55.Cr III-V semiconductors
73.21.Cd Superlattices
78.47.-p Spectroscopy of solid state dynamics

Fabrication of silicon thin films with defects below detection limit of electron spin resonance for solar cells by high-speed zone-melting crystallization of amorphous silicon

Manabu Ihara, Shuhei Yokoyama, Chiaki Yokoyama, Koichi Izumi, and Hiroshi Komiyama

Appl. Phys. Lett. 79, 3809 (2001); http://dx.doi.org/10.1063/1.1421231 (3 pages) | Cited 5 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Silicon (Si) thin films with very-low defect density for solar cells were fabricated by using high-speed (0.7–4.5 mm/s) zone-melting crystallization (ZMC) of amorphous-silicon (a-Si) thin films, resulting in films that had defects below the detection limit of electron spin resonance (ESR). In this letter, poly-crystalline silicon (poly-Si) films for zone-melting recrystallization (ZMR) and a-Si films for ZMC were each sandwiched between two SiO2 films. The Si films were 0.3–2.0 μm thick, the top SiO2 films were 0.35–1.5 μm thick, and the bottom SiO2 films were 0.18–1.2 μm thick. The a-Si ZMC films had higher crystal quality than did the poly-Si ZMR films. Over 90% of the grains in the a-Si ZMC films had preferred (100) orientation when the films were formed at scan speeds 0.7–4.5 mm/s. Transmission electron microscopy (TEM) revealed that neither distinct grain boundaries nor defects were visible in the a-Si ZMC films within the 9-μm-diam observation field. The a-Si ZMC films fabricated from the a-Si films with the thickness smaller than 1 μm had no voids. Such a low defect density indicates that silicon thin-film solar cells with high efficiency can be fabricated by using such very-low defect density silicon thin films. © 2001 American Institute of Physics.
Show PACS
81.05.Cy Elemental semiconductors
81.10.Fq Growth from melts; zone melting and refining
76.30.-v Electron paramagnetic resonance and relaxation
84.60.Jt Photoelectric conversion
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.

Single-electron transistor based on a silicon-on-insulator quantum wire fabricated by a side-wall patterning method

D. H. Kim, S.-K. Sung, J. S. Sim, K. R. Kim, J. D. Lee, B.-G. Park, B. H. Choi, S. W. Hwang, and D. Ahn

Appl. Phys. Lett. 79, 3812 (2001); http://dx.doi.org/10.1063/1.1421081 (3 pages) | Cited 15 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We propose and implement a promising fabrication technology for geometrically well-defined single-electron transistors based on a silicon-on-insulator quantum wire and side-wall depletion gates. The 30-nm-wide silicon quantum wire is defined by a combination of conventional photolithography and process technology, called a side-wall patterning method, and depletion gates for two tunnel junctions are formed by the doped polycrystalline silicon sidewall. The good uniformity of the wire suppresses unexpected potential barriers. The fabricated device shows clear single-electron tunneling phenomena by an electrostatically defined single island at liquid nitrogen temperature and insensitivity of the Coulomb oscillation period to gate bias conditions. © 2001 American Institute of Physics.
Show PACS
85.35.Gv Single electron devices
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
73.63.Nm Quantum wires
85.40.Hp Lithography, masks and pattern transfer

Investigation of oxidation mechanism for ohmic formation in Ni/Au contacts to p-type GaN layers

Chi-Sen Lee, Yow-Jon Lin, and Ching-Ting Lee

Appl. Phys. Lett. 79, 3815 (2001); http://dx.doi.org/10.1063/1.1425065 (3 pages) | Cited 24 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
To investigate the function and mechanisms of oxidation, we present the ohmic performances for Ni/Au contacts to p-type GaN treated with various conditions. When the p-type GaN sample was preoxidized at 750 °C for 30 min in air ambient and then treated with (NH4)2Sx solution, we routinely obtained a specific contact resistance of 4.5×10−6 Ω cm2 for the Ni/Au contacts to samples alloyed at 500 °C for 10 min in air ambient. The fact that, in this configuration, ohmic performance improved one order of magnitude [compared with (NH4)2Sx surface treatment], is attributable to the strengthened formation of GaOx (aided by the preoxidation process), as well as the fact that more holes were induced on the oxidation-free p-type GaN surface. © 2001 American Institute of Physics.
Show PACS
73.40.Ns Metal-nonmetal contacts
81.65.Mq Oxidation
73.40.Cg Contact resistance, contact potential
79.60.Jv Interfaces; heterostructures; nanostructures
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close