A high electron mobility phonotransistor

Abstract

Acoustoelectric devices convert acoustic energy to electrical energy and vice versa. Devices working at much higher acoustic frequencies than those currently available have potential scientific and technological applications, for example, as detectors in phononics experiments and as transducers in bulk acoustic wave filters at terahertz (THz) frequencies. Here we demonstrated an active acoustoelectronic device based on a GaAs heterostructure: an acoustically gated transistor or phonotransistor. Instead of being controlled in the conventional manner by an electrical signal applied to a metallic or semiconductor gate as in a high electron mobility transistor (HEMT), the drain-source current was controlled by a bulk sub-THz acoustic wave passing through the channel in a direction perpendicular to the current flow.

Beyond the ordinary acoustoelectric effect: superluminal phenomena in the acoustic realm and phonon-mediated Bloch gain

“…Both dependencies have pronounced features at the same values of U . However, in contrast to the low-frequency case presented in the left panel Fig.7(a) the high-frequency dependencies indicate more features also related to U crn(9) for n > 2. Importantly, these high-frequency (short-wavelength) acoustic excitations can induce the reverse of the electron drift (v d < 0) due to mechanisms discussed in Section II.…”

“…In the past few years, there has been an intensive research aimed to study the connection between physics of coherent phonons excitation and nonequilibrium dynamics in electronic systems. Prominent examples include phononic devices based on twodimensional (2D) materials [7][8][9][10] which can exhibit high electron mobility [9,10], high-frequency phonon transducers [11][12][13] and quantum structures where coherent acoustic phonons have been generated in the THz-GHz range [7,[14][15][16]. Recently, there has been increased interest in amplification of acoustic phonons due to their interaction with fast moving carriers in semiconductor superlattices (SLs) [16].…”

Beyond the ordinary acoustoelectric effect: Superluminal phenomena in the acoustic realm and phonon-mediated Bloch gain

“…From physical point of view, Eqs. (9) imply multiphonon resonances in a transition scattering of the sound wave by electrons [44] placed in the SL periodic potential. Specifically, the second term in Eq.…”

“…In the past few years, there has been an intensive research aimed to study the connection between physics of coherent phonons excitation and nonequilibrium dynamics in electronic systems. Prominent examples include phononic devices based on two-dimensional (2D) materials [7][8][9][10] which can exhibit high electron mobility [9,10], high-frequency phonon transducers [11][12][13], and quantum structures where coherent acoustic phonons have been generated in the THz-GHz range [7,[14][15][16]. Recently, there has been increased interest in amplification of acoustic phonons due to their interaction with fast moving carriers in semicon-ductor superlattices (SLs) [16].…”

High-speed modulation of a terahertz quantum cascade laser by coherent acoustic phonon pulses

“…Acoustoelectric effects are important in microwave technologies, for example in filters 25 , delay lines 26 and modulators 27 . It has been demonstrated previously that bulk acoustic waves with 100-GHz frequencies can dynamically alter the electrical and mechanical properties of semiconductor heterostructures on length-scales comparable to the epitaxial-layer thickness, which can modulate the electron transport in tunnelling 28 and planar 29 devices, as well as the light emission from quantum dot lasers 30 . Here, we use an optically generated picosecond acoustic (strain) pulse 31 , propagating along the growth direction of a QCL, to modulate its band structure and electron transport on ultrafast timescales.…”