Direct demonstration of a misfit strain-generated electric field in a [111] growth axis zinc-blende heterostructure

Abstract

We report the first direct demonstration of a strain-generated built-in electric field in a (111) oriented strained-layer heterostructure. We present a model which describes the accommodation of the misfit strain in a lattice-mismatched quantum well, and the resulting generation of a longitudinal electric field via the piezoelectric effect. On a (111)B GaAs substrate, we grew the quantum well in the intrinsic region of a p-i-n diode such that the strain-generated electric field in the quantum well opposes the weaker built-in electric field of the diode. Under reverse bias operation, photoconductivity measurements show a quadratic blue shift of the quantum well electroabsorption peaks, in contrast to the red shifts normally observed in the quantum-confined Stark effect. The measured blue shifts demonstrate an electric field strength of 1.7×105 V/cm, which agrees with theory to within the accuracy of the measured sample characteristics.

Numerical study for enhancement-mode AlN/GaN/AlN N-polar MISFET with self-aligned source/drain regions

“…t GaN is used to represent the thickness of the GaN channel. The fabrication process is presented in detail in [11].The two fields from polarization effect respectively between in the GaN/AlN/GaN layer are offset to deplete the two-dimensional electron gas underneath the gate, meanwhile 2DEG under both the sidewall access and source access regions is maintained because of the removal of the AlN layer from the access regions, as shown in Fig.1…”

“…The lattice mismatch between GaN and the ternary compound AlGaN or binary AlN in appropriately designed structures produces strain induced polarization fields [9,10] . A compound material stacks like sandwich can be utilized to offset polarization fields from the two interfaces in order to deplete twodimensional electron gas underneath the gate to realize the E-mode operation [11] . It is not certain whether this kind of device can work in E-mode operation as the gate length enters nano-scale region as well.…”

Electromechanical Fields in Quantum Heterostructures and Superlattices

“…a periodic repetition of well and barriers) are exactly the same, with the lattice constants in the well layers adapting to those of the barrier (Poccia et al, 2010). Calculations for the [111] growth direction of zincblende crystals yields the following analytical expression for the compressional strain in the quantum well (Duggen et al, 2008): Caridi et al (1990) b J.I. Izpura et al (1999) It can be seen that it does not play a role whether one uses the fully-coupled or the semi coupled approach for the nitrides.…”

“…We use linear interpolation to obtain parameters for non-binary compounds. Caridi et al (1990) b Auld (1990) c Fonoberov & Balandin (2003) d Average from Willatzen et al (2006) and Chin et al (1994) e Chin et al (1994) f Davydov (2002) Optoelectronics -Devices and Applications is the second part of an edited anthology on the multifaced areas of optoelectronics by a selected group of authors including promising novices to experts in the field. Photonics and optoelectronics are making an impact multiple times as the semiconductor revolution made on the quality of our life.…”

Monte Carlo Transport Studies of GaN High Electron Mobility Transistors (HEMTs) for Microwave Applications

“…The third-order intercept point (IP3) can be obtained from (34) and ( is predicted for temperatures as high as 600 K, while the room temperature peak is nearly 2.6 X 10^ cm/s, which translates into a 30-percent increase over that for GaAs. These results also indicate that high-field drift velocities for the wurzite phase are larger than those reported for zinc blende GaN.…”