Solid source molecular beam epitaxial growth of In_0.48Ga_0.52P on GaAs substrates using a valved phosphorus cracker cell

School of Electrical and Electronic Engineering (Block S2), Nanyang Technological University, Nanyang Avenue, Singapore 639798, Republic of Singapore

Corresponding author: esfyoon@ntu.edu.sg

Received: 30 November 1998
Revised: 18 February 1999
Accepted: 11 May 1999
Published online: 15 August 1999

Abstract

We report the molecular beam epitaxial growth of InGaP on GaAs (100) substrate using a valved phosphorus cracker cell at various substrate temperatures (T_s from 420 °C to 540 °C). Sample characterization was carried out using Raman scattering (RS), photoluminescence (PL) and X-ray diffraction (XRD). Surface morphology characterization was performed using scanning electron microscopy (SEM). Typical InGaP layers showed a lattice mismatch of < 10⁻³ and PL full-width at half maximum (FWHM) of ~ 7 meV at 10 K. The Raman spectrum showed peaks at 330 cm⁻¹, 360 cm⁻¹ and 380 cm⁻¹ corresponding to the transverse-optic (TO), InP-like longitudinal-optic (LO) and GaP-like LO modes, respectively. No Raman signals were detected from the sample grown at substrate temperature (T_s) of 540 °C, due to poor surface morphology arising from indium desorption. A marginal increase in ordering, as evidenced from the slight decrease (~ 30 meV) in the PL peak energy was seen in samples grown at increasing substrate temperature. Furthermore, no significant variation in the FWHM of the LO modes, TO mode and intensity ratio of the TO mode to the InP-like LO mode were observed, suggesting that any ordering in the material grown using this technique is weak.