Thermal hysteresis loop, dynamical breakdown, and emission-current spike in quantum-well photodetectors

Abstract

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Physics of non-adiabatic transport and field-domain effect in quantum-well infrared photodetectors

“…More recently, a counterclockwise hysteresis loop for the tunneling current and a clockwise hysteresis loop for the emission current in QWIPs was seen experimentally as the device temperature was swept up from 10 to 300 K and then back down [4]. These new phenomena found in QWIPs were physically explained by a non-adiabatic sequential-tunneling model [5]. The non-adiabatic effect discussed in this paper refers …”

“…7(b) shows the comparison between non-adiabatic Hartree po- , the symmetry of log 10 jI na ðtÞj with respect to the positive (electrons being removed) and negative (electrons being added) peaks of E b ðtÞ is broken in the non-adiabatic case (upper solid curve). A small offset [5] of the non-adiabatic log 10 jI na ðtÞj relative to E b ðtÞ ¼ 0 can be seen by comparing upper and lower solid curves.…”

“…In the classical field-domain model [6,8], quantum properties of electrons in QWs have been ignored. On the other hand, it has also been shown that the quantum non-adiabatic effects give rise to a residual current at zero of applied ac voltage due to a space-charge-field effect in the presence of a uniform ac electric field [2,5,11,12]. Therefore, it is very important to include, simultaneously, both the classical field-domain effect and the quantum non-adiabatic effect on the sequential tunneling of electrons in MQWs when an ac electric field is applied to the sample.…”

“…We further introduce a spatially-averaged nonadiabatic space-charge field E na ðtÞ which is defined by [5,11,12]…”

Offset in the dark current characteristics of photovoltaic double barrier quantum well infrared photodetectors

“…AlAs 20 Å explain the common origin of the transient behaviour of electrons in QWIPs (including hysteresis and time-dependent offsets changing magnitude and polarity with scan procedure) [18], whereas it has been suggested the appearance of a time-independent offset could be due to dopant segregation [7] (also the explanation of the observed I d asymmetry [16] and the PV effect [11,12]). On the other hand, in our case, the different metals used in the fabrication of the top and bottom ohmic contacts (AuGe-Au and In-Sn, respectively) do not seem to give rise to the offset, because the same result is obtained when both contacts are made by AuGe-Au within the same metallization process.…”