Light sensitive memristor with bi-directional and wavelength-dependent conductance control

P. Maier, F. Hartmann, M. Rebello Sousa Dias, M. Emmerling, C. Schneider, L. K. Castelano, M. Kamp, G. E. Marques, V. Lopez-Richard, L. Worschech, S. Höfling
2016 Applied Physics Letters  
Semiconductor quantum dots embedded in optoelectronic devices are appealing for applications such as lasers, 1 single photon sources, 2 spin memories 3 and floating gate transistors. 4 Floating gate transistors are key building blocks of flash memories and store information by means of localized charge on a floating gate. 5 Tuning the amount of charge with gate terminals allows to change the resistance of a nearby twodimensional electron gas (2-DEG). 6 Realizing floating gates with quantum dots
more » ... s with quantum dots based on III-Vsemiconductors further provides optical and wavelength-selective control of the resistance, 7-9 which can be exploited for single photon detection 10 or optical memories. 11, 12 In addition, floating gate transistors can be used to realize a memristive operation mode. 13, 14 Memristors are passive fundamental circuit elements with a voltage controllable resistance 15,16 and promising candidates for future computing architectures with inherent memory. 17 The realization of optoelectronic memristors with optical readout, 18-20 optoelectronic tuning of the resistance state 21-23 and light-induced one-directional conductance change 24-26 allows to perform arithmetic operations. 25, 27 Controlling memristors solely by light and realizing photonic synapses however requires bi-directional optical tuning of the resistance. 28 In addition, wavelength-dependent conductance control is beneficial for sensory applications and enables optical communication of electronic devices by converting information of the wavelength to a resistance. 25 We present bi-directional and wavelength-dependent conductance changes of a quantum dot memristor. The memristor is realized on the mature III-V-semiconductor material platform and the conductance corresponds to different amounts of localized electrons on positioned quantum dots (QDs). Illumination of the device with infrared and red light allows to increase and decrease the conductance via intraband and interband absorption, respectively. The presented device is based on a modulation doped GaAs/AlGaAs heterostructure. A wire and lateral gates are defined via electron beam lithography and dry chemical etching (see Fig. 1(a) ). QDs are
doi:10.1063/1.4955464 fatcat:gfthkzavxvbrtnp7ariv6e5hdi