Temperature and excitation dependent photoluminescence of undoped and nitrogen‐doped ZnSe epilayers

Abstract

The photoluminescence (PL) properties of ZnSe epitaxial layers grown by metal-organic vapor phase epitaxy are investigated. A correlation between the electron-hole plasma (EHP) band position and the PL intensity is found and on this basis the nonequilibrium carrier lifetime z and the PL efficiency r] are estimated in the ZnSe layers: z = to lo-'' s, r] = 0.1 to 0.001%. It is shown that these paraneters decrease with decreasing layer thickness and with increasing concentration of contaminations and native defects. The influence of the excitation level and temperature on the intensity and peak position of the band at 472 nm in ZnSe : N and the band at 620 nm in undoped ZnSe epilayers at 78 K grown at temperatures of T, > 500 "C are studied. It is supposed that these bands are due to recombinations described in the configurational coordinate model.

II–VI nanowire radial heterostructures

“…Compared to the peak at 8 K, the luminescence peak from the nanowires at 77 K was 1/3 as intense, and located at 440.5 nm rather than at 439.5 nm. PL emission peaks for ZnSe thin films deposited by MOVPE at 330 • C also red-shifted by 1 nm over a similar temperature range [29]. Figure 4(b) also shows that at 8 K an additional less intense peak at 432 nm was detected, which we attribute to the higher order, E 12 , quantized state for the nanowire emission polarized perpendicular to the growth direction.…”