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1.
A. I. D’Souza P. S. Wijewarnasuriya R. E. Dewames G. Hildebrandt J. Bajaj D. D. Edwall J. G. Pasko J. M. Arias 《Journal of Electronic Materials》1999,28(6):611-616
Excess low frequency noise is investigated for the first time in infrared MBE grown LWIR Hg1−xCdxTe double layer planar heterostructure (DLPH) detectors grown on lattice matched substrates. LWIR detectors having R0Aopt values at 40K in the 101–107 Θ-cm2 range have been characterized as a function of temperature between 120 and 20K. Detectors with R0Aopt≥103Θ-cm2 at 40K have theoretical diffusion limited performance down to 78K and detectors with R0Aopt ≥105 Θ-cm2 at 40K are within a factor of two of theoretical diffusion limited performance for T>65K. Activation energies extracted from
noise (Vd=−100 mV) and dark current (Vd=−100 mV) vs temperature measurements were detector dependent. The activation energy for detectors with R0Aopt≈106 Θ-cm2 at 40K is ∼0.90*Eg to 0.99*Eg. The noise measured between 78 and 105K in the intermediate performance (R0Aopt∼103–104 Θ-cm2 at 40K) detectors are higher than the noise measured in the higher performance (R0Aopt∼105–107 Θ-cm2) detectors. In addition, the excess low frequency noise and the dark current at −100 mV in the intermediate and poor (R0Aopt∼101 Θ-cm2) performance detectors are temperature independent. For each detector measured, the activation energy extracted from noise
(Vd=−100 mV) vs temperature measurements is equal to the activation energy extracted from the total dark current (Vd=−100 mV) vs temperature measurements. For different dark current mechanisms, the excess low frequency noise varies with temperature
and also with area within statistical accuracy in the same manner as the total dark current through the detector. At 78K,
the Tobin14 expression holds in the general sense for equal area detectors dominated by different current mechanisms and also for detectors
with a wide range of implant dimensions (Aimp=3.85×10−7 cm2 to Aimp=6.25×10−4 cm2). Following measurements, the detectors were stripped of the passivation and overlaying metal layers and dressed by a defect
etch to reveal defects in each detector. A correlation among noise, leakage current and defect type has been determined for
each detector. 相似文献
2.
K. J. Bachmann F. S. L. Hsu F. A. Thiel H. M. Kasper 《Journal of Electronic Materials》1977,6(4):431-448
The heat capacities at constant pressure have been measured for CuInSe2, CuInTe2 and AgGaTe2 in the temperature range 1K ≤T≤40K and for CuInS2 and AgInTe2 between 1 K and room temperature. From the low temperature data we derive the following Debye temperatures θD in the limit T → O K: θD(CuInS2) = 273 K, θD(CuInSe2) = 222 K, θD(CuInTe2) = 191 K, θD(AgGaTe2) = 182 K and θD(AgInTe2) = 156 K. A plot of the average atomic heat capacity at constant volume Cv shows that the data scale to one general curve for all 5 compounds considered in this paper. This is, also, true for a plot
Cv, i.e., all I-III-VI2 compounds measured thus far deviate similarly from the Debye approximation. By integration of the general curves Cv(T/θD) and θD x Cv(T/θD) we derive tne standard entropies S
0
298
and energies E
0
298
-E
0
0
of 11 compounds of the type I-III-VI2, for which the Debye temperatures are known. The difference between the energies E
0
298
-E
0
0
and enthalpies H
0
298
-H
0
0
is within the error limits of the experimental data (< 1%). The molar S
0
298
and H
0
298
-H
0
0
values for the I-III-VI2 compounds are approximately twice the corresponding molar values for their II-VI isoelectronic analogs. The thermodynamic
functions at standard state obtained by integration of the experimental data are all < 10% smaller than the corresponding
values estimated on the basis of the Debye approximation. 相似文献
3.
It is shown that lithium-ion intercalation of TlGaSe2 single crystal leads to a shift of the exciton peak associated with the direct edge toward longer wavelengths (ΔE=15 meV at 5 K). As a result, the temperature shift of the exciton peak in TlGaSe2(∂E
ex/∂T) decreases more than twofold in absolute value to −1.1×10−4 eV/K at 20≲T≲105 K and −0.25×10−4 eV/K at 5≲T≲20 K. Lithium-ion (Li+) intercalation of TlGaSe2 has almost no effect on the energy position of the exciton associated with indirect transitions.
Fiz. Tekh. Poluprovodn. 32, 145–147 (February 1998) 相似文献
4.
J. P. André A. Deswarte E. Lugagne-delpon P. Voisin P. Ruterana 《Journal of Electronic Materials》1994,23(2):141-146
(InAs)n(GaAs)n short period superlattices (SPSs) have been successfully grown by a continuous MOVPE process on InP substrates. Their structural,
optical, and electrical properties have been studied. The periodic structures have been confirmed by x-ray measurements and
(InAs)1(GaAs)1 SPSs have been clearly observed by transmission electron microscopic characterization. The optical quality of the material
has been tested by 2K photoluminescence and excitonic recombinations have been observed. Mobilities as high as 10700 cm2.V−1.s−1 and 64000 cm2. V−1.s−1 for a sheet concentration of 3 × 1012 cm−2 have been obtained at 300K and 77K, respectively. 相似文献
5.
Optical measurements are performed in a PbGa2Se4 single crystal. The nature of the optical transitions is determined in the
interval of photon energies 2.24–2.46 eV in the temperature range 77–300 K. It is shown that indirect and direct optical transitions
take place in the energy intervals 2.28–2.35 eV and 2.35–2.46 eV, corresponding to E
gi
=2.228 eV and E
gd
=2.35 eV, respectively, at 300 K. The temperature coefficients of E
gi
and E
gd
are equal to −0.6×10−4 eV/K and −4.75×10−4 eV/K, respectively.
Fiz. Tekh. Poluprovodn. 33, 39–41 (January 1999) 相似文献
6.
We have investigated, as a function of indium content x, the galvanomagnetic and Shubnikov de Haas (SdH) properties of two-dimensional
electron gases (2DEG) formed at lattice matched, strain relaxed InAlAs/InGaAs heterojunctions. These were grown by molecular
beam epitaxy on GaAs misoriented substrates with a two degree offcut toward the nearest (110) plane. Variable temperature
resistivity and Hall measurements indicate an increase in the electron sheet density ns from 0.78×1012cm−2 for x=0.15 to 1.80×1012 cm−2 for x=0.40 at 300K, and from 0.75×1012cm−2 to 1.67×1012cm−2 at T=1.6K. The room temperature electron mobility, measured along the in plane [110], direction is independent of indium
content and equals approximately 9500 cm2/Vs. For T<50K, the mobility is independent of temperature decreasing with increasing x from 82000 cm2/Vs for x=0.15 to 33000 cm2/Vs for x=0.40. The ratios (τt/τq) at 1.6K between the electron relaxation time τt and the single particle relaxation time τq, for the strain relaxed specimens, as well as for pseudomorphically strained Al0.35Ga0.65As/In0.15Ga0.85As structures grown on GaAs substrates, and In0.52Al0.48As/In0.53Ga0.47As heterostructures grown lattice matched on InP substrates. Such a study indicates the presence of inhomogeneities in the
2DEGs of the strain relaxed specimens which appear to be related to the process of strain relaxation. Such inhomogeneities,
however, have little effect on the electron relaxation time τt which, at low temperatures, is limited principally by alloy scattering. 相似文献
7.
S. A. Aliev F. F. Aliev Z. S. Gasanov S. M. Abdullayev R. I. Selim-zade 《Semiconductors》2010,44(6):734-736
The temperature dependences of the heat-conductivity coefficient χ and the thermopower 6h of Ag2S are investigated in the range of 4.2–300 K. It is found that the value of 6h sharply increases (6h ∞ T-3) with decreasing T at T < 100 K and passes through a maximum at 16–18 K. The heat-conductivity coefficient passes through a maximum at ≈30 K. The sharp
increase in 6h is found to be caused by the effect of long-wavelength-phonon drag of electrons. It is shown that the shift
of the 6h and χ peaks, as well as the temperature dependence of the phonon thermopower 6hph ∞ T-3, agrees with the Herring theory. 相似文献
8.
Circular and linear enhancement-mode 6H-SiC MOSFETs for high temperature applications 总被引:1,自引:0,他引:1
Direct current measurements are performed up to 673K at circular and linear (shown in parenthesis) enhancement-mode metal
oxide semiconductor field effect transistors (MOSFETs). These devices are fabricated on a p-type 6H-SiC epitaxial layer with
a doping concentration NA ≈ 1 × 1016 cm−1. The n+ source/drain regions and the p+ regions for the channel stops are achieved by ion implantation of nitrogen and aluminum, respectively. Both MOSFET geometries
show excellent output characteristics with a good saturation behavior even at elevated temperatures. The inversion layer mobility
μn extracted in the linear region is 38 cm2·V−1·s−1 (35 cm2·V−1·s−1) and reveals a weak dependence on temperature with a maximum of 46 cm2·V−1·s−1 (42 cm2·V−1·s−1) at about 473K. Regarding the transfer characteristics, the drain current ID can be well modulated by the gate-source voltage VGS resulting in an Ion/Loff-ratio of 108 (108) at 303K and 105 (106) at 673K. In the subthreshold regime, ID can be pinched off well below 10 pA with a subthreshold swing of 150 mV/decade (155 mV/decade) at room temperature. The threshold
voltage VT as a function of temperature shows two linear sections with negative temperature coefficients of −6.8 mV·K−1 (−6.8 mV·K−1) from 303 to 423K and −2.5 mV·K−1 (−2.0 mV·K−1) from 423 to 673K. By measuring VT as a function of bulk-source voltage VBS at different temperatures, NA can be directly estimated at a transistor and gives 9.6 × 1015 cm−3 (9.8 × 1015 cm−3). The measured bulk Fermi potential Φf of the p-type epitaxial layer deviates less than 10% from the calculated value at a given temperature. 相似文献
9.
The N2-doped 3C-SiC thin films have been grown by low-pressure, chemical vapor deposition (LPCVD) on amorphous Si3N4/p-Si (111) substrates using the single, organosilane-precursor trimethylsilane [(CH3)3SiH]. The effects of N2 flow rate and growth temperature on the electrical properties of SiC films were investigated by Hall-effect measurements.
The electron-carrier concentration is between 1017–1018/cm3. The lowest resistivities at 400 K and 300 K are 1.12×10−2 and 1.18×10−1 cm, respectively. The corresponding sheet resistances are 75.02 Ω/□ and 790.36 Ω/□. The SiC film structure was studied by
x-ray diffraction. The 3C-SiC films oriented in the 〈111〉 direction with a 2ϑ peak at 35.5° and line widths between 0.18–0.25°
were obtained. The SiC/Si3N4 interface is very smooth and free of voids. The fabrication of microelectromechanical (MEMS) structures incorporating the
SiC films is discussed. 相似文献
10.
In this work, a citrate sol–gel method (Sol–Gel) with polyethylene glycol 400 (Sol-Gel-PEG400) was developed to prepare γ-Na
x
Co2O4 by using sodium and cobalt nitrates as the raw materials, citric acid as a complexing agent, and PEG400 as a dispersant.
At 800°C, single-phase γ-Na
x
Co2O4 crystals were obtained using Sol-Gel-PEG400. With the addition of 1 vol.% PEG400, smaller, flaky particles exhibited a well-tiled
structure along the plane direction of the flaky particles. Moreover, polycrystalline sintered bulk γ-Na
x
Co2O4 with more highly oriented crystals and greater compact density was fabricated using the Sol-Gel-PEG400 synthesized powders
compared with the powders synthesized by citrate Sol–Gel. The electrical conductivity (σ) values of Sol-Gel-PEG400 samples were higher than those of Sol–Gel samples between 400 K and 900 K. The σ value of Sol-Gel-PEG400 increased to 3.13 × 104 Sm−1 at 400 K and to 1.84 × 104 Sm−1 at 900 K. Between 400 K and 850 K, the Seebeck coefficient (α) values of Sol-Gel-PEG400 samples were slightly lower than those of Sol–Gel samples. Near 900 K, the α values of these two methods were nearly equal, at 164 μV K−1. Between 400 K and 900 K, the power factor (P) of Sol-Gel-PEG400 was evidently larger than that of Sol–Gel. 相似文献
11.
A. N. Danilewsky S. Lauer J. Meinhardt K. W. Benz B. Kaufmann R. Hofmann A. Dornen 《Journal of Electronic Materials》1996,25(7):1082-1087
GaSb bulk single crystals with low acceptor concentration were grown from a bismuth solution by the traveling heater method.
The result is isoelectronic doping by Bi which gives a variation of the opto-electronic properties as a function of grown
length as well as a pronounced microscopic segregation. Photoluminescence spectra at 4K show a decrease of the natural acceptor
during growth, which is confirmed by Hall measurements. The electrical properties of this isoelectronic doped GaSb are hole
concentrations and mobilities of NA − ND = 1.7 × 1016 cm−3 and μ = 870 cm2Vs at room temperature and NA-ND = 1 × 1016 cm−3 and μ = 4900 cm2/Vs at 77K, respectively. The lowest p-type carrier concentration measured at 300K is NA − ND = 3.3 × 1015 cm−3 相似文献
12.
This study concerns the magnetic properties of single crystals of Fe
x
Mn1 − x
In2S4 alloys. The basically antiferromagnetic character of indirect exchange interactions between Fe2+ and Mn2+ cations is established. As the concentration of Fe2+ cations is increased, the magnetic ordering temperature increases from ∼12 K (x = 0) to ∼22 K (x = 1). Short-range-order ferromagnetic correlations are observed. The basic magnetic phase state of the alloys is the spin
glass state, with the freezing temperature increasing from ∼5 K (x = 0) to ∼12 K (x = 1). As the external magnetic field is increased, the magnetic ordering temperature slightly decreases. The most probable
causes and mechanisms of formation of the magnetic state of the alloys are discussed. 相似文献
13.
We have measured the resistivity ρ and Hall coefficient RH at 300, 77, and 4.2 K of p-type Pb1−XCdXS epitaxial films as a function of substrate temperature Ts, film thickness d, and composition x. The films were vapor deposited on cleaved (111) BaF2 (111) SrF2 , and (001) NaCl and polished (001) BaF2 substrates. The Hall mobility μH at 77 K of p-type PbS films increased approximately linearly from 1 × 104 to 2 × 104 cm2 V−1 sec−1 as Ts was varied from 400 to 500°C, respectively. Both μH and RH increased with d due to the presence of a strong p-type surface layer on the exposed surface. The x of the films was controlled
by the x of the source material and Ts. The mole fraction of CdS could be varied between 0.002 < x < 0.06 by varying T between 513 and 410°C, respectively, and
using source material with x = 0.06. The electrical properties of samples grown on freshly cleaved (111) BaF2 and (111) SrF2 were essentially identical even though the lattice constant of SrF2 is a better match to Pb1−XCdXS than BaF2. The RH and μH at 77 K were independent of thickness for low substrate temperatures and were observed to increase with increasing thickness
for high substrate temperatures. The μH increased with decreasing temperature and became temperature independent below about 30 K, which is similar to the behavior
observed in other lead salt compounds. However, the magnitude of μH was considerable lower throughout the 300 to 4.2 K temperature range than for PbS films. The RH showed little temperature variation, which is typical lead salt behavior.
Supported by Naval Surface Weapons Center Independent Research Funds. 相似文献
14.
M. K. Sharov 《Semiconductors》2012,46(5):595-597
The thermopower coefficient α0 and the electrical conductivity σ of Pb1 − x
Ag
x
Te solid solutions, where x = (0–0.007), are measured at T = 300 K. The hole concentration p is calculated. All samples are of the p type. With increasing silver content, α0 decreases, while p and σ increase. For undoped crystals, α0 = 251.0 μV/K, p = 1.1 × 1018 cm−3, and σ = 165 Ω−1 cm−1. At the silver-solubility limit for x = 0.007, α0 = 193.8 μV/K, p = 2.3 × 1018 cm−3, and σ = 216 Ω−1 cm−1. The hole concentration in all samples is much lower than the concentration of introduced silver atoms. The hole gas in Pb1 − x
Ag
x
Te solid solutions is weakly degenerate in the entire silver-concentration range. 相似文献
15.
M. Razeghi M. A. Poisson J. P. Larivain J. P. Duchemin 《Journal of Electronic Materials》1983,12(2):371-395
The low pressure metalorganic chemical vapor deposition epitaxial growth and characterization of InP, Ga0.47In0.53 As and GaxIn1-xAsyP1-y, lattice-matched to InP substrate are described. The layers were found to have the same etch pit density (EPD) as the substrate.
The best mobility obtained for InP was 5300 cm2 V−1S−1 at 300 K and 58 900 cm2 V−1 S−1 at 772K, and for GaInAs was 11900 cm2 V−1 S−1 at 300 K, 54 600 cm2 V−1 S−1 at 77 K and 90 000 cm V−1S−1 at 2°K. We report the first successful growth of a GaInAs-InP superlattice and the enhanced mobility of a two dimensional
electron gas at a GaInAs -InP heterojunction grown by LP-MO CVD. LP MO CVD material has been used for GaInAsPInP, DH lasers
emitting at 1.3 um and 1.5 um. These devices exhibit a low threshold current, a slightly higher than liquid phase epitaxy
devices and a high differential quantum efficiency of 60%. Fundamental transverse mode oscillation has been achieved up to
a power outpout of 10 mW. Threshold currents as low as 200 mA dc have been measured for devices with a stripe width of 9 um
and a cavity length of 300 um for emission at 1.5 um. Values of T in the range 64–80 C have been obtained. Preliminary life
testing has been carried out at room temperature on a few laser diodes (λ = 1.5μm). Operation at constant current for severalthousand
hours has been achieved with no change in the threshold current. 相似文献
16.
R. M. Sardarli O. A. Samedov A. P. Abdullayev E. K. Huseynov E. M. Qocayev F. T. Salmanov 《Semiconductors》2011,45(8):975-979
Temperature dependences of electrical conductivity σ(T) and permittivity ɛ(T) of one-dimensional (1D) TlGaTe2 single crystals are investigated. At temperatures higher than 305 K, superionic conductivity of the TlGaTe2 is observed and is related to diffusion of Tl+ ions via vacancies in the thallium sublattice between (Ga3+Te22−
− nanochains. A relaxation character of dielectric anomalies is established, which suggests the existence of electric charges
weakly bound to the crystal lattice. Upon the transition to the superionic state, relaxors in the TlGaTe2 crystals are Tl+ dipoles ((Ga3+Te22−)− chains) that arise due to melting of the thallium sublattice and hops of Tl+ ions from one localized state to another. The effect of a field-induced transition of the TlGaTe2 crystal to the superionic state is detected. 相似文献
17.
V. V. Slyn’ko E. I. Slyn’ko A. G. Khandozhko Yu. K. Vygranenko 《Semiconductors》1997,31(10):1021-1024
A study is reported of the nuclear magnetic resonance spectra of 119Sn and 125Te in SnTe with hole concentrations p
77=1.42×1020−2.3×1021 cm−3 and in SnTe:Mn (N
Mn=0.5 and 5 at. %, p
77=8×1020 cm−3) at T=4.2–300 K. Considerable broadening of NMR lines due to hyperfine magnetic interactions between nuclear and electron spins
was observed in SnTe with p
77>2×20 cm−3. Asymmetric broadening of the resonance lines was observed in the rhombohedral phase of SnTe and SnTe:Mn. The temperature
dependence of the NMR line width of 125Te in SnTe:Mn is in agreement with the magnetic phase diagram for N
Mn=5 at. %. The superparamagnetic phase of SnTe:Mn is formed at T=20±2 K and the ferromagnetic phase is formed at T=4.2 K.
Fiz. Tekh. Poluprovodn. 31, 1187–1191 (October 1997) 相似文献
18.
The temperature dependence in the range 77–400 K of the carrier concentration, resistivity and mobility of a series of n and
p-type single crystal, liquid-phase epitaxial layers of Ga1−xAlxAs are presented. These layers were doped, n-type with tellurium, and p-type with germanium to yield carrier concentrations
in the range 1017 – 1018cm−3 at 295 K. Donor and acceptor ionization energies, εD and εA, are derived from the data. The dependence of εD on alloy composition is interpreted in terms of the known band structure variation in the alloy system. 相似文献
19.
E. Belas V. V. Bogoboyashchyy R. Grill I. I. Izhnin A. P. Vlasov V. A. Yudenkov 《Journal of Electronic Materials》2003,32(7):698-702
Time relaxation of the electrical conductivity σ(77 K) and Hall coefficient RH(77 K) of the n-type layer created by ion milling is investigated in Hg vacancy-doped, As-doped, and In-predoped p-type, and
In-doped n-type Hg1−xCdxTe (0.2 < x < 0.22) samples. We show that the n-type layer is formed, and the temperature-activated relaxation occurs in all
cases. The annealing at 75°C results in a gradual degradation of the converted n-type layer and a back n-to-p conversion within
8 days. The existence of a high-conducting, surface-damaged region with a high-electron density (∼1018 cm−3) and a low mobility (∼103 cm2/Vs) is confirmed, and its influence on the relaxation is studied. 相似文献
20.
The electrical resistivity (ρ) and Seebeck coefficient (S) of the three delafossites CuFe0.9Cr0.1O2, CuCr0.98Mg0.02O2, and CuRh0.9Mg0.1O2 have been measured and their power factor (PF) calculated. These p-type oxides show PF values at 800 K from 1.4 × 10−4 W K−2 m−1 to 6.9 × 10−4 W K−2 m−1. In contrast to delafossites containing Fe or Cr, for which ρ exhibits a regime, the Rh-based delafossite shows a metallic regime from 5 K to 1000 K. This points toward the role of the transition-metal
electronic configuration in the transport properties. Otherwise, similar PF values are obtained in the case of the n-type Al-doped ZnO. For these oxides, the ρ and PF values are minimum and maximum, respectively, for x = 0.01. However, the presence of spinel impurities even for x = 0.01 in Zn1−x
Al
x
O or for x = 0.02 in CuCr1−x
Mg
x
O2 calls into question the role of the doping element in the physical properties. This should motivate a deeper insight into
the physics of thermoelectric oxides. 相似文献