THz/sub-THz bolometer based on electron heating in a semiconductor waveguide

Abstract

Direct detection THz/sub-THz bolometer is proposed. In it an electromagnetic wave propagates in the bipolar semiconductor waveguide, heats electrons and holes there, and therefore creates their bipolar thermodiffusion flow and, as well as, the electromotive force (emf). The flow causes the carrier excess concentration. Both this concentration and emf are used to get the bolometer response voltage. The bolometer theoretical model is developed. The possibility without cooling or moderate cooling (about 100 K for the Cd0.2Hg0.8Te bolometers) to get acceptable for applications values of the noise equivalent power is shown. Experimental results confirm the main model conclusions.

In–HgCdTe–In structures with symmetric nonlinear I–V characteristics for sub-THz direct detection

“…At the low biases, the calculated NEP of investigated In-n-Hg 0.61 Cd 0.39 Te-In detectors , when there available are the thermal and shot noises. The presence of Schottky barriers does not affect strongly on the NEP value, as compared to the same structures that were investigated in the framework of hot-electron bolometer theory [9,10].…”

“…The structures of this type were investigated earlier in the framework of hot-electron bolometer theory [9], and it demonstrated sensitivity to radiation in ν = 0.037…1.54 THz frequency range at temperatures T ~70…300 K. However, during studying the electrical characteristics and sensitivity of these structures to radiation, we found that current-voltage characteristics of some samples deviate from linear behavior even at room temperature. In this case, their photoresponse as a function of the bias current does not match the behavior, predicted by the theory for hot-electron bolometer [9] and observed experimentally in Hg 1-x Cd x Te structures with ohmic contacts previously [10]. Some samples had linear current-voltage characteristics at room temperature, but at liquid nitrogen temperature these characteristics were significantly nonlinear.…”

Detection of terahertz and sub-terahertz wave radiation based on hot-carrier effect in narrow-gap Hg1−xCdxTe

“…In this paper, ground of the model is stated only and more de− tailed explanation can be found in Ref. 20. Here, the thin layer of bipolar semiconductor with the concentrations of shallow donors N d and acceptors N a , respectively, is a a sen− sitive element with the thickness a 1 , the width a 2 , and the distance a 3 between the metal contacts which serve as an− tennas.…”

Detection of IR and sub/THz radiation using MCT thin layer structures: design of the chip, optical elements and antenna pattern

“…Under the influence of incident THz radiation, the changes in HEB (hot electron bolometer) sensitive element parameters take place at the length of several micrometers [6] and are much less compared to antenna dimensions, through which the radiation power is introduced to HEB. The antenna dimensions are conditioned by its effective area A eff = Gλ 2 /4π and are close to the wavelength λ, G is the antenna gain [7].…”

“…The use of un-cooled MCT detector as THz with other detection mechanism compared to IR region was offered in [6], where the properties of a free electron gas heated by THz radiation were analyzed. Thus, there is an opportunity varying the characteristics of sensitive layers to apply such MCT detector technology for simultaneous operation in different spectral regions, which makes these systems more informative.…”