Photonics Research, 2017, 5 (3): 03000239, Published Online: Oct. 9, 2018
Direct bandgap photoluminescence from n-type indirect GaInP alloys Download: 709次
Abstract
This work studies Te doping effects on the direct bandgap photoluminescence (PL) of indirect alloys ( ). The temperature-dependent PL shows that the energy difference between direct valley and indirect X valleys is reduced due to the bandgap narrowing (BGN) effect, and the direct band transition gradually dominates the PL spectra as temperature increases. Carrier thermalization has been observed for Te-doped samples, as integrated PL intensity increases with increasing temperature from 175 to 300 K. The activation energy for carrier thermalization is reduced as doping concentration increases. Both BGN effect and carrier thermalization contribute to the carrier injection into the valley. As a result, the direct band transition is enhanced in the Te-doped indirect alloys. Therefore, the PL intensity of the sample with active doping concentration of is increased by five times compared with that of a nominally undoped sample. It is also found that the PL intensity is degraded significantly when the doping concentration is increased to . From cross-section transmission electron microscopy, no large dopant clusters or other extended defects were found contributing to this degradation.
Cong Wang, Bing Wang, Riko I. Made, Soon-Fatt Yoon, Jurgen Michel. Direct bandgap photoluminescence from n-type indirect GaInP alloys[J]. Photonics Research, 2017, 5(3): 03000239.