Below-bandgap excited terahertz emission in GaAs/AlGaAs multiple quantum wells

Authors

Elmer Estacio Institute for Molecular Science, Okazaki, Japan
Alex Quema Institute for Molecular Science, Okazaki, Japan
Gilbert Diwa Institute for Molecular Science, Okazaki, Japan
Carlito Ponseca Institute for Molecular Science, Okazaki, Japan
Glenda de los Reyes Institute for Molecular Science, Okazaki, Japan
Shingo Ono Institute for Molecular Science, Okazaki, Japan
Hidetoshi Murakami Institute for Molecular Science, Okazaki, Japan
Nobuhiko Sarukura Institute for Molecular Science, Okazaki, Japan
Joanes Paulus Sy National Institute of Physics, University of the Philippines Diliman
Armando Somintac National Institute of Physics, University of the Philippines Diliman
Christine Ison National Institute of Physics, University of the Philippines Diliman
Arnel Salvador National Institute of Physics, University of the Philippines Diliman

Abstract

We present terahertz (THz) emission of optically pumped narrow (L_z= 5 nm) and wide (L_z= 12.5 nm) GaAs/AlGaAs multiple quantum wells (MQWs). The THz action spectra (excitation energy dependence of the THz radiation intensity) exhibit emission even at excitation energies below the MQW bandgaps. This observation is exhibited by both samples but is more pronounced in the 5 nm MQW sample. The results are attributed to states below the first conduction band energy level, possibly due to impurity levels that were incorporated during the molecular beam epitaxy (MBE) growth process. Although photoluminescence, photoluminescence excitation, and reflectivity data did not reveal these below-gap features, the presence of shallow traps are confirmed by deep level transient spectroscopy (DLTS) experiments.

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Issue

2005: Proceedings of the 23rd Samahang Pisika ng Pilipinas Physics Congress

Article ID

SPP-2005-3B-01

Section

Materials Science

Published

2005-10-26

How to Cite

[1]

E Estacio, A Quema, G Diwa, C Ponseca, G de los Reyes, S Ono, H Murakami, N Sarukura, JP Sy, A Somintac, C Ison, and A Salvador, Below-bandgap excited terahertz emission in GaAs/AlGaAs multiple quantum wells, Proceedings of the Samahang Pisika ng Pilipinas 23, SPP-2005-3B-01 (2005). URL: https://proceedings.spp-online.org/article/view/SPP-2005-3B-01.