Title :
Terahertz emission from InGaN LED structures: excitation energy and bias dependence study
Author :
Sohn, J.Y. ; Yahng, J.S. ; Park, D.J. ; Oh, E. ; Kim, D.S. ; Sanders, G.D. ; Stanton, C.J. ; Citrin, D.S.
Author_Institution :
Sch. of Phys., Seoul Nat. Univ., South Korea
Abstract :
Summary form only given. The electro-optic sampling method is used for detecting THz emission from InGaN LED structures excited by a frequency-doubled femtosecond Ti:sapphire laser. The intrinsic layer consists of 5 wells of In/sub 0.15/Ga/sub 0.85/N (2 nm) and 4 barriers of GaN (10 nm). The signal amplitude is strongly dependent on the bias voltage. As the reverse bias goes up, the signal amplitude increases. Oscillations with 8-9 ps periods are observed, which corresponds almost exactly with the total intrinsic layer thickness divided by the sound velocity of the system. A remarkable ringing over several THz cycles is observed. While we do not yet understand the precise origin, it might suggest the involvement of acoustic wave packets traveling within the layer structures.
Keywords :
III-V semiconductors; gallium compounds; indium compounds; light emitting diodes; quantum well devices; semiconductor quantum wells; submillimetre wave spectra; 10 nm; 2 nm; Franz-Keldysh effect; In/sub 0.15/Ga/sub 0.85/N-GaN; InGaN LED structures; acoustic wave packets; bias dependence; electro-optic sampling method; excitation energy dependence; frequency-doubled femtosecond Ti:sapphire laser; intrinsic layer; long-period oscillation; reverse bias; ringing; signal amplitude; strongly strained system; terahertz emission; Gallium compounds; Indium compounds; Light-emitting diodes; Quantum wells; Submillimeter wave spectroscopy;
Conference_Titel :
Quantum Electronics and Laser Science Conference, 2002. QELS '02. Technical Digest. Summaries of Papers Presented at the
Conference_Location :
Long Beach, CA, USA
Print_ISBN :
1-55752-708-3
DOI :
10.1109/QELS.2002.1031288
