@article {297, title = {Relaxation times in InAs/AlSb quantum wells }, journal = {Applied Physics Letters}, volume = {72}, year = {1998}, chapter = {2439}, doi = {10.1063/1.121377}, url = {https://aip.scitation.org/doi/abs/10.1063/1.121377}, author = {Markelz, A. G. and Asmar, N. G. and Gwinn, E. G.} } @article {266, title = {Interband impact ionization by terahertz illumination of InAs heterostructures}, journal = {Applied Physics Letters}, volume = {69}, number = {26}, year = {1996}, note = {ISI Document Delivery No.: VY894
Times Cited: 91
Cited Reference Count: 17
Cited References:
ASMAR NG, 1995, PHYS REV B, V51, P18041, DOI 10.1103/PhysRevB.51.18041
Asmar NG, 1996, APPL PHYS LETT, V68, P829, DOI 10.1063/1.116547
BAIER HU, 1986, SOLID STATE COMMUN, V58, P327, DOI 10.1016/0038-1098(86)90094-3
BLOEMBER.N, 1974, IEEE J QUANTUM ELECT, VQE10, P375, DOI 10.1109/JQE.1974.1068132
BOLOGNESI CR, 1994, IEEE ELECTR DEVICE L, V15, P16, DOI 10.1109/55.289476
CERNE J, 1995, PHYS REV B, V51, P5253, DOI 10.1103/PhysRevB.51.5253
GANICHEV SD, 1986, ZH EKSP TEOR FIZ+, V90, P445
GAUER C, 1994, SEMICOND SCI TECH, V9, P1580, DOI 10.1088/0268-1242/9/9/002
Kochman B, 1996, APPL PHYS LETT, V68, P1936, DOI 10.1063/1.115631
MARKELZ AG, 1994, SOLID STATE ELECTRON, V37, P1243, DOI 10.1016/0038-1101(94)90399-9
MARKELZ AG, 1994, SEMICOND SCI TECH, V9, P634, DOI 10.1088/0268-1242/9/5S/063
NGUYEN C, 1993, J VAC SCI TECHNOL B, V11, P1706, DOI 10.1116/1.586509
NGUYEN C, 1993, J ELECTRON MATER, V22, P255, DOI 10.1007/BF02665035
TUTTLE G, 1990, J APPL PHYS, V67, P3032, DOI 10.1063/1.345426
Walpole J. N., 1971, Journal of Applied Physics, V42, P5609, DOI 10.1063/1.1659990
WHITE CRH, 1991, APPL PHYS LETT, V58, P1164, DOI 10.1063/1.104352
XIE H, 1994, J APPL PHYS, V76, P92, DOI 10.1063/1.357065
Markelz, AG Asmar, NG Brar, B Gwinn, EG
Markelz, Andrea/0000-0003-0443-4319
92

6
Amer inst physics
Melville
1077-3118}, month = {Dec}, pages = {3975-3977}, type = {Article}, abstract = {

Experimental studies of InAs heterostructures illuminated by far-infrared (FIR) radiation reveal an abrupt increase in the charge density for FIR intensities above a threshold value that rises with increasing frequency. We attribute this charge density rise to interband impact ionization in a regime in which omega tau(m) similar to 1, where tau(m) is the momentum relaxation time, and f=omega/2 pi is the FIR frequency. The dependence of the density rise on the FIR field strength supports this interpretation, and gives threshold fields of 3.7-8.9 kV/cm for the frequency range 0.3-0.66 THz. (C) 1996 American Institute of Physics.

}, keywords = {energy, far-infrared excitation, inas/alsb quantum-wells, inplane, modulation, Physics}, isbn = {0003-6951}, doi = {10.1063/1.117842}, author = {Markelz, A. G. and Asmar, N. G. and Brar, B. and Gwinn, E. G.} } @article {268, title = {Nonlinear response of quantum-confined electrons in nonparabolic subbands}, journal = {Journal of Applied Physics}, volume = {80}, number = {4}, year = {1996}, note = {7}, month = {Aug 15}, pages = {2533-2535}, abstract = {

We show that quantum confinement can dramatically alter the density-dependence of the third-order susceptibility, chi(NP)((3)) that arises from band nonparabolicity. Our results predict an oscillatory dependence of the efficiencies for third-harmonic generation and four-wave mixing on the subband occupation of quantum wells, and for narrow wells with high charge densities predict an enhancement over the bulk susceptibility. We also make a simple estimate of the fields required to saturate this nonparabolicity contribution to chi((3)). We discuss these results in light of recent experiments on third-harmonic generation from narrow-gap quantum wells at frequencies of similar to 1 THz, and show that nonparabolicity may not be the only nonlinearity contributing to the large chi((3)) observed. (C) 1996 American Institute of Physics.

}, isbn = {0021-8979}, doi = {10.1063/1.363040}, author = {Markelz, A. G. and Gwinn, E. G.} } @article {258, title = {Temperature of quasi-two-dimensional electron gases under steady-state terahertz drive}, journal = {Applied Physics Letters}, volume = {68}, number = {6}, year = {1996}, note = {ISI Document Delivery No.: TT663
Times Cited: 59
Cited Reference Count: 12
Cited References:
ASMAR NG, 1995, PHYS REV B, V51, P18041, DOI 10.1103/PhysRevB.51.18041
BETHUNE DS, 1989, J OPT SOC AM B, V6, P910, DOI 10.1364/JOSAB.6.000910
CERNE J, 1995, PHYS REV B, V51, P5253, DOI 10.1103/PhysRevB.51.5253
CONWELL E, 1967, SOLID STATE PHYS S, V9
GUPTA R, 1992, PHYS REV B, V46, P7745, DOI 10.1103/PhysRevB.46.7745
HEYMAN JN, 1994, PHYS REV LETT, V72, P2183, DOI 10.1103/PhysRevLett.72.2183
KOMIYAMA S, 1985, PHYS REV B, V32, P5532, DOI 10.1103/PhysRevB.32.5532
MARKELZ AG, 1994, SOLID STATE ELECTRON, V37, P1243, DOI 10.1016/0038-1101(94)90399-9
MARKELZ AG, 1995, THESIS U CALIFORNIA
SHAH J, 1984, APPL PHYS LETT, V44, P322, DOI 10.1063/1.94739
SHAH J, 1978, SOLID STATE ELECTRON, V21, P43, DOI 10.1016/0038-1101(78)90113-2
YANG CH, 1985, PHYS REV LETT, V55, P2359, DOI 10.1103/PhysRevLett.55.2359
Asmar, NG Cerne, J Markelz, AG Gwinn, EG Sherwin, MS Campman, KL Gossard, AC
Sherwin, Mark S/Q-4762-2017
Sherwin, Mark S/0000-0002-3869-1893; Markelz, Andrea/0000-0003-0443-4319
59

7
Amer inst physics
Woodbury}, month = {Feb}, pages = {829-831}, type = {Article}, abstract = {

We use photoluminescence to study the time-average energy distribution of electrons in the presence of strong steady-state drive at terahertz (THz) frequencies, in a modulation-doped 125 Angstrom AlGaAs/GaAs square well that is held at low lattice temperature TL. We find that the energy distribution can be characterized by an effective electron temperature, T-e(\>T-L), that agrees well with values estimated from the THz-illuminated, dc conductivity. This agreement indicates that under strong THz drive, LO phonon scattering dominates both energy and momentum relaxation; that the carrier distribution maintains a heated, thermal form; and that phonon drift effects are negligible. (C) 1996 American Institute of Physics.

}, keywords = {hot-electrons, Physics}, isbn = {0003-6951}, doi = {10.1063/1.116547}, author = {Asmar, N. G. and Cerne, J. and Markelz, A. G. and Gwinn, E. G. and Sherwin, M. S. and Campman, K. L. and Gossard, A. C.} } @article {259, title = {RESONANT-ENERGY RELAXATION OF TERAHERTZ-DRIVEN 2-DIMENSIONAL ELECTRON GASES}, journal = {Physical Review B}, volume = {51}, number = {24}, year = {1995}, note = {Sherwin, Mark S/Q-4762-2017
Sherwin, Mark S/0000-0002-3869-1893; Markelz, Andrea/0000-0003-0443-4319
119}, month = {Jun 15}, pages = {18041-18044}, isbn = {0163-1829}, doi = {10.1103/PhysRevB.51.18041}, author = {Asmar, N. G. and Markelz, A. G. and Gwinn, E. G. and Cerne, J. and Sherwin, M. S. and Campman, K. L. and Hopkins, P. F. and Gossard, A. C.} } @article {260, title = {DC TRANSPORT IN INTENSE, INPLANE TERAHERTZ ELECTRIC-FIELDS IN AL(X)GA(1-X)AS HETEROSTRUCTURES AT 300-K}, journal = {Solid-State Electronics}, volume = {37}, number = {4-6}, year = {1994}, note = {Markelz, Andrea/0000-0003-0443-4319
6th International Conference on Modulated Semiconductor Structures
Aug 23-27, 1993
Garmisch partenkir, germany
Tech univ munchen, walter schottky inst
1}, month = {Apr-Jun}, pages = {693-695}, abstract = {

We report 300 K studies of the dependence of the in-plane, d.c. conductivity, sigma(d.c.) (E(omega)), of a quasi 2D electron gas on the amplitude E(omega) and frequency of intense, far-infrared fields (omega/2pi = 0.24-3.5 THz). We measure sigma(d.c.) (E(omega) parallel-to E(d.c.)), where E(d.c.) is a small sensing field, and observe a monotonic decrease in sigma(d.c.) with increasing E(omega). Although a simple scaling ansatz collapses the measured sigma(d.c.) (E(omega)) data onto a single curve for frequencies from 0.25-3.45 THz (at low to moderate scaled fields), the decrease in conductivity is substantially more rapid than expected from comparison to similar data taken by Masselink et al. [Solid-St. Electron. 31, 337 (1988)] at 35 GHz. We tentatively attribute this difference to effects of a high-frequency modulation in the electron temperature.

}, isbn = {0038-1101}, doi = {10.1016/0038-1101(94)90278-X}, author = {Asmar, N. G. and Markelz, A. G. and Gwinn, E. G. and Hopkins, P. F. and Gossard, A. C.} } @article {261, title = {ENERGY RELAXATION AT THZ FREQUENCIES IN ALXGA1-XAS HETEROSTRUCTURES}, journal = {Semiconductor Science and Technology}, volume = {9}, number = {5}, year = {1994}, note = {Markelz, Andrea/0000-0003-0443-4319
S
8th International Conference on Hot Carriers in Semiconductors
Aug 16-20, 1993
Oxford univ, oxford, england
Sci \& engn res council; royal soc; brit council; oxford univ
2}, month = {May}, pages = {828-830}, abstract = {

We report 4.2 K studies of the dependence of the in-plane, DC conductivity of a quasi 2D electron gas on the amplitude E(omega) of applied fields with frequencies from 0.25 THz to 3.5 THz. We analyse the dependence of sigma(DC) on E(omega) assuming that electron-optical phonon scattering dominates energy relaxation, that the absorbed power has a Drude form and that the electron distribution is thermal. This simple analysis is self-consistent: Arrhenius plots of the estimated energy loss rate have a slope near -homega(LO)BAR/k(B) for all frequencies, as expected for energy loss by optical phonon emission. We find that the effective energy relaxation time tau(epsilon) varies with the frequency of the applied field, from tau(epsilon) approximately 4 ps at 0.34 THz to tau(epsilon) approximately 0.3 ps at 3.45 THz. This may indicate a frequency-dependent form for the hot-phonon distribution.

}, isbn = {0268-1242}, doi = {10.1088/0268-1242/9/5S/116}, author = {Asmar, N. G. and Markelz, A. G. and Gwinn, E. G. and Hopkins, P. F. and Gossard, A. C.} } @proceedings {319, title = {Far-infrared harmonic generation from semiconductor heterostructures}, volume = {1854}, year = {1994}, pages = {48-55}, author = {Markelz, A.G. and Gwinn, E. G. and Sherwin, M. S. and Heyman, J. N. and Nguyen, C. and Kroemer, H.} } @proceedings {318, title = {Frequency Dependence of the Third Order Susceptibility of InAs Quantum Wells at Terahertz Frequencies}, year = {1994}, month = {08/1994}, pages = {1193-1196}, author = {Markelz, A.G. and Cerne, J. and Gwinn, E. G. and Brar, B. and Kroemer, H.} } @article {269, title = {GIANT 3RD-ORDER NONLINEAR SUSCEPTIBILITIES FOR INPLANE FAR-INFRARED EXCITATION OF SINGLE INAS QUANTUM-WELLS}, journal = {Solid-State Electronics}, volume = {37}, number = {4-6}, year = {1994}, note = {Sherwin, Mark S/Q-4762-2017
Sherwin, Mark S/0000-0002-3869-1893; Markelz, Andrea/0000-0003-0443-4319
6th International Conference on Modulated Semiconductor Structures
Aug 23-27, 1993
Garmisch partenkir, germany
Tech univ munchen, walter schottky inst
9}, month = {Apr-Jun}, pages = {1243-1245}, abstract = {

Third-order, free-carrier nonlinear susceptibilities, chi(3), have been measured between 19 and 23 cm-1 for three InAs/AlSb quantum wells with sheet densities between 2.5 x 10(12) cm-2 and 8 x 10(12) cm-2. We find that these wells are strongly nonlinear at far-infrared frequencies: odd harmonics ninth order have been observed at high incident intensities, and the peak value of chi(3) reaches approximately 1 esu. This is several orders of magnitude larger than previously reported values for chi(3) in bulk n-GaAs (10(-4) esu)[1] and in polyacetylene (10(-7) esu)[2]. The large magnitude of chi(3) is attributed to the high carrier density in the InAs wells, and to the strong non-parabolicity of the conduction band in InAs. However, the free-carrier chi(3) for bulk InAs predicts a density-dependence different from that observed, and the measured decrease in chi(3) with increasing intensity indicates non-perturbative response. We find that the anisotropy of chi(3) displays the expected 4-fold symmetry.

}, isbn = {0038-1101}, doi = {10.1016/0038-1101(94)90399-9}, author = {Markelz, A. G. and Gwinn, E. G. and Sherwin, M. S. and Nguyen, C. and Kroemer, H.} } @article {267, title = {SUBCUBIC POWER DEPENDENCE OF 3RD-HARMONIC GENERATION FOR INPLANE, FAR-INFRARED EXCITATION OF INAS QUANTUM-WELLS}, journal = {Semiconductor Science and Technology}, volume = {9}, number = {5}, year = {1994}, note = {Sherwin, Mark S/Q-4762-2017
Sherwin, Mark S/0000-0002-3869-1893; Markelz, Andrea/0000-0003-0443-4319
S
8th International Conference on Hot Carriers in Semiconductors
Aug 16-20, 1993
Oxford univ, oxford, england
Sci \& engn res council; royal soc; brit council; oxford univ
4}, month = {May}, pages = {634-637}, abstract = {

Large third-order, free-carrier nonlinear susceptibilities, chi(3) (to approximately 0.2 esu), and subcubic dependence of the third-harmonic power on the incident intensity, have been observed between 19 cm-1 and 23 cm-1 for InAs/AlSb quantum wells with electron sheet densities between 2.5 x 10(12) cm-2 and 8 X 10(12) cm-2. We find that the transmission of the fundamental, and the samples{\textquoteright} DC conductivity, decrease with increasing incident intensity, indicating a large rise in the scattering rate. Using the intensity-dependent transmission to account for absorption in the sample is not sufficient to recover a cubic power law for the third-harmonic intensity. In addition, given the increased scattering rate indicated by the conductivity data, the bulk free-carrier chi(3) due to non-parabolicity should decrease dramatically with increasing fundamental intensity, contrary to our results. Thus, non-parabolicity alone cannot account for the observed third-harmonic response.

}, isbn = {0268-1242}, doi = {https://doi.org/10.1088/0268-1242/9/5S/063}, author = {Markelz, A. G. and Asmar, N. G. and Gwinn, E. G. and Sherwin, M. S. and Nguyen, C. and Kroemer, H.} } @proceedings {320, title = {Far-infrared nonlinear response of electrons in semiconductor nanostructures}, volume = {1854}, year = {1993}, pages = {36-47}, author = {Sherwin, M. S. and Asmar, N. G. and Bewley, W. W. and Craig, K. and Felix, C. L. and Galdrikian, B. and Gwinn, E. G. and Markelz, A.G. and Gossard, A. C. and Hopkins, P. F. and Sundaram, M. and Birnir, B.} }