Spectroscopic Study of Tellurium Donors in GaP

The $1s\left(A_1\right)\to 2p_0 \mathrm{and} 2p_{\pm }$ transitions in Te donors in GaP have been observed. Together with similar data for Si and S donors, Faulkner's effective-mass (EM) calculations yield an ionization energy of 89.8±0.3 meV for Te donors. Conduction-band effective masses consistent with all the data for these GaP donors are $m_{\perp }=(0.180\mathrm{}\pm 0.005)m_0$ and $m_{\mathrm{II}}=(1.5\mathrm{}\pm 0.2)m_0$. The effects of uniaxial stress on the "two-electron" transitions in the recombination of excitons bound to neutral Te donors in GaP are consistent with the final donor states observed being $s$-like with a valley-orbit splitting.