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Deep Level Transient Spectroscopy in Quantum Dot Characterization  [cached]
Engstr?m O,Kaniewska M
Nanoscale Research Letters , 2008,
Abstract: Deep level transient spectroscopy (DLTS) for investigating electronic properties of self-assembled InAs/GaAs quantum dots (QDs) is described in an approach, where experimental and theoretical DLTS data are compared in a temperature-voltage representation. From such comparative studies, the main mechanisms of electron escape from QD-related levels in tunneling and more complex thermal processes are discovered. Measurement conditions for proper characterization of the levels by identifying thermal and tunneling processes are discussed in terms of the complexity resulting from the features of self-assembled QDs and multiple paths for electron escape.
Current mode deep level transient spectroscopy on semiconductor nanowire field effect transistor  [PDF]
Ivan Isakov,Marion J L Sourribes,Paul A Warburton
Physics , 2014,
Abstract: In this paper we report the characterization of electrically-active deep levels in a single ZnO nanowire by current-mode deep level transient spectroscopy (I-DLTS). ZnO nanowires were grown by plasma-assisted molecular-beam epitaxy. Contacts to nanowires were patterned using electron beam lithography. Gate voltage bias was used to fill the deep traps. Both surface and core traps were observed in I-DLTS spectra. Models of surface and electron and hole-like traps are proposed and implemented to discuss I-DLTS results.
Deep level transient spectroscopy investigation of deep levels in CdS/CdTe thin film solar cells with Te:Cu back contact

Wang Zhao,Li Bing,Zheng Xu,Xie Jing,Huang Zheng,Liu Cai,Feng Liang-Huan,Zheng Jia-Gui,

中国物理 B , 2010,
Abstract: Deep levels in Cds/CdTe thin film solar cells have a potent influence on the electrical property of these devices. As an essential layer in the solar cell device structure, back contact is believed to induce some deep defects in the CdTe thin film. With the help of deep level transient spectroscopy (DLTS), we study the deep levels in CdS/CdTe thin film solar cells with Te:Cu back contact. One hole trap and one electron trap are observed. The hole trap H1, localized at Ev+0.128~eV, originates from the vacancy of Cd (VCd. The electron trap E1, found at Ec-0.178~eV, is considered to be correlated with the interstitial Cui= in CdTe.
Electronic properties and deep level transient spectroscopy of CdS/CdTe thin film solar cells

Li Bing,Feng Liang-Huan,Wang Zhao,Zheng Xu,Zheng Jia-Gui,Cai Ya-Ping,Zhang Jing-Quan,Li Wei,Wu Li-Li,Lei Zhi,Zeng Guang-Gen,

中国物理 B , 2011,
Abstract: It is well known that preparing temperatures and defects are highly related to deep-level impurities. In our studies, the CdTe polycrystalline films have been prepared at various temperatures by close spaced sublimation (CSS). The different preparing temperature effects on CdS/CdTe solar cells and deep-level impurities have been investigated by I--V and C--V measurements and deep level transient spectroscopy (DLTS). By comparison, less dark saturated current density, higher carrier concentration, and better photovoltaic performance are demonstrated in a 580oC sample. Also there is less deep-level impurity recombination, because the lower hole trap concentration is present in this sample. In addition, three deep levels, Ev+0.341 eV(H4), Ev+0.226 eV(H5) and EC-0.147 eV(E3), are found in the 580oC sample, and the possible source of deep levels is analysed and discussed.
Luminescence and deep-level transient spectroscopy of grown dislocation-rich Si layers
I. I. Kurkina,I. V. Antonova,A. A. Shklyaev,S. A. Smagulova
AIP Advances , 2012, DOI: 10.1063/1.4748863
Abstract: The charge deep-level transient spectroscopy (Q-DLTS) is applied to the study of the dislocation-rich Si layers grown on a surface composed of dense arrays of Ge islands prepared on the oxidized Si surface. This provides revealing three deep-level bands located at EV + 0.31 eV, EC – 0.35 eV and EC – 0.43 eV using the stripe-shaped p-i-n diodes fabricated on the basis of these layers. The most interesting observation is the local state recharging process which proceeds with low activation energy (~50 meV) or without activation. The recharging may occur by carrier tunneling within deep-level bands owing to the high dislocation density ~ 1011 - 1012 cm-2. This result is in favor of the suggestion on the presence of carrier transport between the deep states, which was previously derived from the excitation dependence of photoluminescence (PL) intensity. Electroluminescence (EL) spectra measured from the stripe edge of the same diodes contain two peaks centered near 1.32 and 1.55 μm. Comparison with PL spectra indicates that the EL peaks are generated from arsenic-contaminated and pure areas of the layers, respectively.
Investigation of electronic trap states in organic photovoltaic materials by current-based deep level transient spectroscopy  [PDF]
Stefan Neugebauer,Julia Rauh,Carsten Deibel,Vladimir Dyakonov
Physics , 2012, DOI: 10.1063/1.4731637
Abstract: Current-based deep level transient spectroscopy was used to study trap states in poly(3- hexylthiophene-2,5-diyl) (P3HT), [6,6]-phenyl-C61 butyric acid methyl ester (PCBM) and P3HT:PCBM blend. The obtained spectra showed traps of 87 meV activation energy in pure P3HT and 21 meV for PCBM. The blend shows a complex emission rate spectrum consisting of several different emission rate bands in the range of (0.1-30) s^-1, yielding activation energies between about 30 meV and 160 meV.
Characterization of Interface Traps in SiO$_2$/SiC Structures Close to the Conduction Band by Deep-Level Transient Spectroscopy  [PDF]
Tetsuo Hatakeyama,Mitsuru Sometani,Yoshiyuki Yonezawa,Kenji Fukuda,Hajime Okumura,Tsunenobu Kimoto
Physics , 2014, DOI: 10.7567/JJAP.54.111301
Abstract: The effects of the oxidation atmosphere and crystal faces on the interface-trap density was examined by using constant-capacitance deep-level transient spectroscopy to clarify the origin of them. By comparing the DLTS spectra of the low-mobility interfaces oxidized in a N$_2$O atmosphere with those of the high-mobility interfaces on C-face oxidized in a wet atmosphere, it was found that a high density of traps are commonly observed around the energy of 0.16 eV from the edge of the conduction band ($C1$ traps) in low-mobility interfaces irrespective of crystal faces. It was also found that the generation and elimination of traps specific to crystal faces: (1) the $C1$ traps can be eliminated by wet oxidation only on the C-face, and (2) the $O2$ traps (0.37 eV) can be observed in the SiC/SiO$_2$ interface only on the Si-face. The generation of $O2$ traps on the Si-face and the elimination of $C1$ traps on the C-face by wet oxidation may be caused by the oxidation reaction specific to the crystal faces.
Electrical Transport Characteristics and Deep Level Transient Spectroscopy of Ni/V/n-InP Schottky Barrier Diodes  [PDF]
S.Sankar Naik,V.Rajagopal Reddy
Journal of Nano- and Electronic Physics , 2012,
Abstract: We report on the temperature-dependent electrical characteristics and deep level transient spectroscopy (DLTS) of the Ni/V/n-InP Schottky diodes in the temperature range of 180-420 K. Current density - voltage (J-V) characteristics of these diodes have been analyzed on the basis of thermionic emission theory with Gaussian distribution model of barrier height. The calculated Schottky barrier height ( bo) and ideality factor (n) of Ni/V Schottky contact is in the range of 0.39 eV and 2.36 at 180 K, and 0.69 eV and 1.27 at 420 K, respectively. It is observed that the zero-bias barrier height increases while ideality factor decreases with increasing temperature. A bo versus q/2kT plot is drawn to obtain evidence of a Gaussian distribution of the barrier heights, and values of = 0.95 eV and 0 = 128 eV for the mean barrier height and standard deviation. A modified Richardson plot gives (T=0)= 0.98 eV and Richardson constant (A*) = 7.068 A K – 2cm – 2. The discrepancy between Schottky barrier height (SBHs) estimated from J-V and C-V measurements is also discussed. Thus, it is concluded that the temperature dependence of J-V characteristics of the SBHs on n-InP can be explained on the basis of themionic emission mechanism with Gaussian distribution of the barrier heights. DLTS results showed that two deep levels are identified (E1 and E2) in as-grown sample having activation energies of 0.29 ± 0.01 and 0.69 ± 0.02 with capture cross-section 3.29 × 10 – 15 cm2 and 5.85 × 10 – 17 cm2 respectively.
AlGaInP LEDs with surface anti-reflecting structure
表面增透结构AlGaInP LED的研究

Chen Yixin,Shen Guangdi,Li Jianjun,Han Jinru,Xu Chen,
陈依新
,沈光地,李建军,韩金茹,徐晨

半导体学报 , 2009,
Abstract: A kind of AlGaInP light emitting diode (LED) with surface anti-reflecting structure has been introduced to solve the problems of low light efficiency and restricted luminous intensity. The new structure can be demonstrated theoretically and experimentally
Electronic Excited State and Vibrational Dynamics of Water Solution of Cytosine Observed by Time-resolved Transient Absorption Spectroscopy with Sub-10fs Deep Ultraviolet Laser Pules  [cached]
Miyazaki Jun,Kida Yuichiro,Kobayashi Takayoshi.
EPJ Web of Conferences , 2013, DOI: 10.1051/epjconf/20134105017
Abstract: Time-resolved transient absorption spectroscopy for water solution of cytosine with sub-10fs deep ultraviolet laser pulse is reported. Ultrafast electronic excited state dynamics and coherent molecular vibrational dynamics are simultaneously observed and their relaxation mechanisms are discussed.
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