Linewidth and dephasing of THz-frequency collective intersubband transitions in a GaAs/AlGaAs quantum well

✍ Scribed by J.B Williams; M.S Sherwin; K.D Maranowski; C Kadow; A.C Gossard

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 126 KB
• Volume: 7
• Category: Article
• ISSN: 1386-9477
• DOI: 10.1016/s1386-9477(99)00320-3

✦ Synopsis

Terahertz-frequency intersubband (ISB) transitions in semiconductor quantum wells are of interest due to the potential for making devices that operate at THz frequencies, and the in uence of many-body interactions on the intersubband dynamics. We present measurements of the linear absorption linewidth of ISB transitions in a single 40 nm delta-doped GaAs=Al 0:3Ga0:7As square quantum well, with a transition energy of order 10 meV (3 THz). Separate back-and front-gates allow independent control of charge density (0.1-1 × 10 10 cm -2 ) and DC bias (-2:5-0:5 mV=nm). A picture of scattering of the intersubband plasmon into single-particle excitations qualitatively explains the DC bias dependence of the line-width data.