Photothermal ionization identification of residual donors in high purity InP grown by gas source molecular beam epitaxy

Abstract

Residual donors in the high purity InP epitaxial layer grown by gas source molecular beam epitaxy (GSMBE) have been identified by a photothermal ionization technique in a magnetic field. The dominant residual donors in GSMBE InP are identified to be silicon and sulfur. The Zeeman effect of the hydrogenic donors has also been investigated. The 1s–3p photothermal ionization transitions of the hydrogenic donors are observed even at zero magnetic field. The photoconductivity transition related to the LO phonon is observed and discussed. Furthermore, the photothermal ionization transitions arising from different chemical donors are also clearly resolved in a magnetic field. From the spectral peaks in magnetic field, the electron effective mass m* in GSMBE InP is estimated to be (0.0817±0.0002)m₀.