Nanoscale physics

Ambipolar drift of charge carriers in the long base of the lateral planar diode in the AlGaAs/GaAs/AlGaAs quantum well 
Vainberg V.V., Pylypchuk A.S., Poroshin V.N., Belevskii P.A.,
Vinoslavski M.N.
Solid State Electronics Department, Institute of Physics of the NAS of Ukraine. Prospect Nauki, 46, Kyiv-03039, Ukraine. 
E-mail: vainberg@iop.kiev.ua; viktor.vainberg@gmail.com

The ambipolar drift of electrons and holes in the long base planar diode in the AlGaAS/GaAs/AlGaAs quantum well (QW) with a delta-layer of the Si donor impurity in the barrier at the distance of 10 nm has been investigated at 300 and 77 K in the ranges of 0 to 1000 V (forward bias) and 0 to 12 V (reverse bias). The heterostructures were grown by the MOVPE method on the (100)-plane of semi-insulating GaAs substrates with the Al content of 15%. They consisted of 10 periods with the 8 nm wide QWs and 80 nm wide barriers. NSi= 5.41011 or 11011 cm−2. The diodes were 1.8 mm wide and 6 mm long QW strips with the 4 mm long base. The p-n-junction was made by doping with Zn. The delta-layer forms a 2D potential well supplying electrons into the compositional QW. The bipolar drift of electrons with injected holes modulates the serial resistance of the base by changing the resulting mobility and bipolar drift length.
The measured current-voltage characteristics (CVC) in the small forward bias range show a usual for p-n-junctions superlinear behavior while at the high voltages CVC sharply decreases its slope. The obtained results are explained basing on the model proposed in [1]. In consequence of the real space transfer of electrons at high biases from the compositional QW into the delta-layer the spatial separation of electrons and holes occurs over the parallel channels in the diode base because the valence band QW in such structures does not exist in the delta-layer. It results, in its turn, in an increased recombination time and bipolar drift length in the diode base. The obtained results are useful for application in optoelectronics
The work was supported by the project No.82/19-H (the complex program “Fundamental problems of creation of new nanomaterials and nanotechnologies”).

1.	V.V. Vainberg, O.G. Sarbey, A.S. Pylypchuk, V.N. Poroshin, N.V. Baidus. A peculiarity of quantum hot-electron real space transfer in dualchannel GaAs-based heterostructures. // J. Phys. Commun. -2017. - 1 – 045002.