Ultrafast carrier dynamics in III-V semiconductors grown by molecular-beam epitaxy at very low substrate temperatures

Gupta, Sandeep; Whitaker, J.F.; Mourou, G.

doi:10.1109/3.159553

Cited by 325 publications

(149 citation statements)

References 31 publications

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“…This, along with other research [17], appears to provide evidence that the fast response of LT-GaAs may not be due to the precipitates, which are present only in the post-annealed material, but that deep levels arising from the excess arsenic or other point or structural defects are mainly responsible. Several studies also confirm that this ultrashort carrier lifetime cannot be sustained as the growth temperature is increased [23]. For instance, by the time growth temperatures are increased only to 250-300°C, carrier lifetimes measured by this technique are typically > 50 ps.…”

Section: Ultrashort Carrier Lifetimementioning

confidence: 75%

“…This pump-induced change in absorption, Aa(t), and the corresponding change in reflection, evolve along with the carrier population due to a number of phenomena. Because most of these processes occur on a slow timescale, however, the relaxation decay of the reflection and the transmission (or Act) are influenced mainly by trapping/recombination at deep levels [23]. Figure 2 shows the normalized fractional transmissivity changes for two as-grown and two annealed LTGaAs samples grown at 190 and 200°C.…”

Section: Ultrashort Carrier Lifetimementioning

confidence: 99%

“…To reach the bandgap associated with 1.5/zm light, a material such as In0.53Ga0.47As, which is sensitive down to 1.7/am, is needed. Unfortunately, even though In0.53Ga0.47As grown on InP has been demonstrated to have a carrier lifetime of 2.5 ps when grown at 180 °C [23], it has a very low resistivity and thus is not a candidate for use in high-speed infrared detectors. It has been recently discovered, however, that LT-InxGa~_xAs grown lattice-mismatched on GaAs, with InAs mole fractions as high as 35%, does have a moderately high resistivity to go along with a picosecond carrier lifetime [23].…”

Section: Low-temperature-grown Inxga I _ Xasmentioning

confidence: 99%

“…In one investigation [23], two MSM structures were integrated on one wafer of LT-GaAs (Fig. 7, inset), where one behaved as the detector (in the shunt position), and one served as a sampling gate.…”

Section: Lt-gaas Photodetectors and Photoswitchesmentioning

confidence: 99%

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Optoelectronic applications of LTMBE III–V materials

Whitaker

1993

Materials Science and Engineering: B

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A review of the application of semiconductor layers grown at low substrate temperatures to ultrafast optoelectronics is presented. The films, grown by molecular beam epitaxy primarily around 200 °C and subsequently annealed, are demonstrated to have high resistivity, high mobility, an ultrashort carrier lifetime, and a high dielectric breakdown. This combination of properties makes the low-temperature-grown materials perfectly suited for use in high-speed optoelectronic devices. A number of issues which influence the application of these materials, such as growth temperature, use of an annealing process, layer thickness, and optical wavelength, are considered. Examples of low-temperature-grown semiconductor optoelectronic devices, including ultra-high-bandwidth photoconductive detectors, high-sensitivity, highbandwidth MSM photodetectors, and optical temporal analyzers are demonstrated. While the discussion concentrates on low-temperature-grown GaAs, the lattice-mismatched ternary compound InxGa ~ _xAs/GaAs is also considered in the context of detection of the longer wavelengths used in optical communications.

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Section: Ultrashort Carrier Lifetimementioning

confidence: 75%

Section: Ultrashort Carrier Lifetimementioning

confidence: 99%

Section: Low-temperature-grown Inxga I _ Xasmentioning

confidence: 99%

Section: Lt-gaas Photodetectors and Photoswitchesmentioning

confidence: 99%

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Optoelectronic applications of LTMBE III–V materials

Whitaker

1993

Materials Science and Engineering: B

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“…After growth, however, proper in situ or ex situ annealing at 600 °C is necessary in order increase the density of arsenic precipitates and hence resistivity of this layer [60]. A high density (>10 18 cm -3 ) of arsenic precipitates in LTG-GaAs results in excess arsenic-related point defects and a short carrier trapping time [61]. Due to the high resistivity and extremely short carrier trapping time (~200 fs) of LTGGaAs, carrier drift time, dark current and depletion layer thickness are of considerably less importance for the construction of high-power, highspeed LTG-GaAs-based photodiodes.…”

Section: Millimeter-wave Photonic Transmittersmentioning

confidence: 99%

Millimeter-wave photonic wireless links for very high data rate communication

2011

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T he most useful wireless communication band is located in the frequency range of 0.3-3.5 GHz for reasons of compact antenna size, low propagation loss and good penetration through buildings [1]. However, wireless carrier frequencies are being pushed higher due to emerging high-bandwidth applications, which include next-generation smart cell phones [1] and wireless linking for three-dimensional super high-definition television [2]. As a result, the millimeter-wave (MMW) bands at 60 (V-band), 120 (D-band) and even higher than 300 GHz are beginning to attract attention due to their 'unlicensed' usage [2][3][4][5][6][7][8].Several key front-end components have been developed employing the already mature silicon-based complementary metal-oxide-semiconductor (CMOS) integrated-circuit (IC) technology for wireless communication in the V (50-75 GHz) and W (75-110 GHz) bands or even higher operating frequencies for wireless communication [9]. Recently, a 60 GHz CMOS transceiver module [10] and system comprised of antennas, 60 GHz power amplifiers, local oscillators and baseband ICs has been commercially developed by SiBEAM (USA). In addition, advanced InP-based high electron mobility transistors (InP-HEMTs) and heterojunction bipolar transistors have been used to develop some high-speed ICs and key components that operate at 125 GHz [11,12] or greater than 300 GHz [13,14] for >1 Gbit s -1 wireless communication systems.However, MMW signals suffer substantial propagation loss in free space [8]. This problem and their inherent straight-line path of propagation affect connections and synchronization between the different parts of the whole communication system [15]. A promising solution to overcome this problem is the radio-over-fiber (RoF) technique [3,4,16,17], in which the MMW local-oscillator signal and data are both distributed through a low-loss optical fiber and only radiated over the last mile to the end user. Figure 1 shows a schematic representation of this approach, illustrating the motivation and working principles of two MMW-over-fiber communication systems. Figure 1(a) shows the additional electrical-to-optical (E-O) and optical-to-electrical (O-E) conversion processes used in the central office and base station, respectively. The optical MMW signal is distributed remotely through a low-loss fiber from the central office to several base stations, effectively eliminating the huge propagation loss of the MMW signal that occurs in an electrical transmission line or free space.

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