Full text loading...
(a) Microscope image of a device, showing mesas and upper electrodes. (b) Schematic illustration of the cross section of the mesa structure. (c) Diagram of detection system.
I–V characteristics (a) and bolometer response in B-1 at 50 K as a function of either bias current (b) or voltage (b). In (d), I–V characteristics of B-1 at temperatures from 20 to 64 K with an interval of 2 K are plotted. For all panels, colored symbols represent bolometric detections of THz wave with the detected power being scaled by color-bar in the panel (d). A red rectangle in (a) corresponds to the axes of the blow-up plot shown in Fig. 3(a). Thick red arrows indicate onset and end of the high-bias emission when bias is decreased.
Blow-up plots of quasiparticle branch of I–V characteristics in mesas B-1 (a) and C-1 (b) at 50 K. Small voltage steps shown by red arrows are found at onset and offset of emission whereas no voltage step was found in C-1. Inset in (b) is entire I–V characteristics of C-1. Colors in (a) represent detected intensity as scaled by color-bar.
Sample used in this study and their values for te , Tc , Ic at ∼20 K, the voltage and temperature ranges where THz radiation was observed. A-2a and 2b are on the same crystal chip. No emission was observed in the two C-type devices.
Article metrics loading...