Quasiadiabatic electron transport in room temperature nanoelectronic devices induced by hot-phonon bottleneck

Abstract

Since the invention of transistors, the flow of electrons has become controllable in solid-state electronics. The flow of energy, however, remains elusive, and energy is readily dissipated to lattice via electron-phonon interactions. Hence, minimizing the energy dissipation has long been sought by eliminating phonon-emission process. Here, we report a different scenario for facilitating energy transmission at room temperature that electrons exert diffusive but quasiadiabatic transport, free from substantial energy loss. Direct nanothermometric mapping of electrons and lattice in current-carrying GaAs/AlGaAs devices exhibit remarkable discrepancies, indicating unexpected thermal isolation between the two subsystems. This surprising effect arises from the overpopulated hot longitudinal-optical (LO) phonons generated through frequent emission by hot electrons, which induce equally frequent LO-phonon reabsorption (“hot-phonon bottleneck”) cancelling the net energy loss. Our work sheds light on energy manipulation in nanoelectronics and power-electronics and provides important hints to energy-harvesting in optoelectronics (such as hot-carrier solar-cells).

Direct Observation of Hot-Electron-Enhanced Peltier Effects in Silicon Nanodevices

“…This conclusion has been confirmed in multiple devices with similar structure and dimensions. This result is consistent with the observation in nanocontricted GaAs channel 35,36 but is opposite to the previous report obtained in long nano-crystalline Si microwire channel 40 where minor carriers enhance the Thomson effect and cause lattice overheating within the long channel (entrance side of majority carriers).…”

“…More measurements under different biases and on different devices confirm similar behaviors. It is noteworthy to point out that, unlike in GaAs 35,36 where asymmetric hotspot for Te-pattern was observed, no appreciable asymmetry was found here within the biased range (up to 10 V). This implies that the electron transport here can be viewed as diffusive and local in this dimension, without involving nonlocal energy dissipation mechanism seen in GaAs.…”

“…In contrast, SThM is contact nanothermometry which probes the local TL-distribution using a scanning thermocouple tip. Details for the measurement principle and methods of SNoiM/SThM can be found elsewhere 36 (also see "Methods" and Supplementary Note 3 and 4). All the thermometric measurements are carried out at ambient temperature (TRoom~300 K) and atmospheric pressure.…”

Numerical Modeling and Performance Evaluation of SnS Based Heterojunction Solar Cell with p+ SnS BSF Layer

“…With the increase in the temperature, the electrons become excited and the movements of the free carriers get obstructed due to lattice vibrations. Hence the e ciency reduced due to thr collision with the heavily energized electrons [ 34 ].…”

Properties and challenges of hot-phonon physics in metals: MgB$_2$ and other compounds

“…In real systems (as well as in a variety of more refined theoretical modeling), the coupling between the electron and lattice degrees of freedom gives rise to a phonon distribution function b q,ν ({f, b}) which may differ significantly from the thermal unperturbed one b (0) q,ν , affecting as well the resulting steady electronic function f k ({f, b}). The role of a non-thermal b q,ν ({f, b}), initially regarded as "phonon disturbance" have been experimentally detected and theoretically investigated for a long time, especially in high electric-field regime, and it becomes more evident under hot-phonon conditions, where only few lattice modes are excited by the coupling with the electrons [70,71,76,78,137,[140][141][142][143].…”