Scintillation studies of CdS(In): effects of various semiconductor doping strategies

We present room-temperature photoluminescence and pulsed X-ray measurements of powder samples of CdS(In) codoped with three hole traps (Te, Ag, and Na). Te is an isoelectronic hole trap and Ag and Na are acceptor hole traps. The emission of CdS(In) excited at 430 nm is centered at ≈520 nm (near the band edge) with ≈20 nm FWHM. The emissions from CdS(Te) and the three codoped samples are shifted to longer wavelengths and are characterized by broad emission bands peaking near 630 nm.Whereas the decay of the CdS(Te) emission is nonexponential with times >10 ns, the decay of CdS(In,Te) is 3.3 ns and exponential over three decades. The decay of the acceptor-doped samples CdS(In,Ag) and CdS(In,Na) are also fast, 2.5 and 2.8 ns, respectively. These results show the potential for developing fast inorganic scintillators based on direct-gap semiconductors that can be codoped to provide fast radiative recombination. Additional work is needed to increase the luminosity.