Evidence for sequential tunnelling and charge build-up in double barrier resonant tunnelling devices

Observation of space-charge bulk-up and thermalisation in an asymmetric double-barrier resonant tunnelling structure

“…In this letter we report how studies of magneto-oscillations in the differential capacitance can be used to monitor both the space-charge build-up in the quantum well and in the accumulation layer of the emitter contact. In contrast to previous studies of magnetoquantum oscillations in symmetric DBSS [8,9], we find that the quasi-Fermi level of the electrons stored in the well lies significantly below the Fermi level of the electrons in the emitter accumulation layer. We attribute this to energy relaxation of the stored charge distribution which will occur if the electron storage time in the quantum well is sufficiently long.…”

Charge build-up and intrinsic bistability in an asymmetric resonant-tunnelling structure

“…This indicates that on resonance charge builds up in the quantum well rather than in the emitter accumulation layer. We estimate that the electron density in the well builds up to around 2 X 10" cm-' at the -0.7 V peak, significantly higher than in previous studies [3,4]. In forward bias, n, grows steadily with V , indicating that there is little charge build-up in the well.…”

“…function of magnetic field have clcarly demonstrated charge build-up in the well above the threshold voltage for resonant tunnelling [3,4]. However, Sollner [S] argued that the bistability which Goldman and coworkers observed in the I ( V ) characteristics of their DRS is not an intrinsic property of the DBS itself, but is due to high-frequency oscillations in the current when the DBS is biased in the region of negative differential conductivity (NDC).…”

Resistance switching memory operation using the bistability in current–voltage characteristics of GaN/AlN resonant tunneling diodes

“…15,16) Moreover, electrons accumulating in the quantum well owing to the intersubband transitions are not easily transferred from the quantum well to the collector, because the AlN barrier has a height of 1.8 eV and the coherence and tunneling contributions to the current are destroyed by the intersubband transitions. [17][18][19][20] Therefore, high-speed write-read-erase-read memory operations and long-time storage of data can be realized using resistance switching memories based on GaN=AlN RTDs. A detailed explanation for the resistance switching memory operations, which includes the changes in band structure and I-V curve caused by the accumulation and release of electrons in the quantum well, is described in Ref.…”