Electrooptic and converse-piezoelectric properties of epitaxial GaN/Si structures for optoelectronic applications

Mireille Cuniot-Ponsard (1) , Irma Saraswati (2, 3) , S.-M. Ko (4) , Mathieu Halbwax (2, 5) , Y.-H. Cho (4) , N.-R. Poespawati (3) , El Hadj Dogheche (2, 5, 6)

1 Laboratoire Charles Fabry / Manolia
2 IEMN - Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520
3 UI - Universitas Indonesia
4 Department of Physics and KI for the Nano-Century
5 OPTO - IEMN - Optoélectronique - IEMN
6 IEMN-DOAE - Institut d’Électronique, de Microélectronique et de Nanotechnologie - Département Opto-Acousto-Électronique - UMR 8520

In order to take advantage in all-optic optoelectronic devices, we have investigated the optical and piezoelectric properties of GaN films deposited on (111) silicon. Films are epitaxially grown by MOCVD, thanks to a buffer made of (Al, Ga) N intermediate layers [1]. Structural properties of GaN are analyzed using TEM and the influence of threading dislocations density is discussed. Optical properties are investigated using a prism coupling [2]. Electrooptic measurements are performed using an original technique [3]. A semi-transparent gold electrode is deposited on top of GaN layer and an alternating voltage is applied between top and bottom electrodes. The electro-optic, converse piezoelectric, and electro-absorptive coefficients are simultaneously determined from the measurement of the electric field induced variation ΔR(θ) in the reflectivity of the Au/GaN/buffer/Si stack versus incident angle. The method also enables to determine the GaN layer polarity. The results obtained for a Ga-face [0001] GaN layer when using a modulation frequency of 230 Hz are for the electro-optic coefficients r13 = +1 pm/V, r33 = +1.60 pm/V at 633 nm, and for the transverse piezoelectric coefficient d33 = +4.59 pm/V. The value measured for the electro-absorptive variation is Δko/ΔE = +0.77 pm/V. The electro-optic coefficients for GaN /Si and the electro-absorptive coefficient are measured for the first time. The converse piezoelectric value agrees with values previously reported.

Domaines: Optique [physics.optics]

Mireille Cuniot-Ponsard, Irma Saraswati, S.-M. Ko, Mathieu Halbwax, Y.-H. Cho, et al.. Electrooptic and converse-piezoelectric properties of epitaxial GaN/Si structures for optoelectronic applications. European Materials Research Society Spring Meeting, E-MRS Spring 2014, Symposium K - Challenges for group III nitride semiconductors for solid state lighting and beyond, May 2014, Lille, France. ⟨hal-00961405⟩