Terahertz photoresponse of AlInSb/InSb/AlInSb quantum well structures

Abstract

We have studied the photoresponse (transmission and photoconductivity of Corbino-shaped devices) of structures with InSb quantum wells (AlInSb barriers). To characterize the devices, the Shubnikov-de Haas (SdH) effect up to magnetic fields $B$ of 7 T and current-voltage $(I\text{\ensuremath{-}}V)$ characteristics at various magnetic fields were measured. Some of the samples showed clearly resolvable SdH oscillations. The $I\text{\ensuremath{-}}V$ curves showed pronounced nonlinearities. The phototransmission and the photoconductivity at various terahertz (THz) frequencies were measured around 2.5 THz generated by a $p$-Ge laser. From the cyclotron resonance (transmission measurements) we deduced a cyclotron mass of $0.022{m}_{0}$. We also performed photoconductivity measurements on Corbino-shaped devices in the THz frequency range. Oscillations of the photoconductivity with maxima near the minima of the conductivity in the dark were observed. Thus, these devices are potentially suitable for the detection of THz radiation.