Direct bandgap photoluminescence from n-type indirect GaInP alloys

作     者：CONG WANG BING WANG RIKO I.MADE SOON-FATT YOON JURGEN MICHEL 

作者机构：School of Electrical and Electronic EngineeringNanyang Technological University Low Energy Electronic SystemsSingapore-MIT Alliance for Research and Technology Department of Materials Science and EngineeringMassachusetts Institute of Technology 

出 版 物：《Photonics Research》 (光子学研究（英文版）)

年 卷 期：2017年第5卷第3期

页      面：239-244页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：National Research Foundation Singapore(NRF) 

主　　题：type in is on of for Direct bandgap photoluminescence from n-type indirect GaInP alloys BGN from 

摘      要：This work studies Te doping effects on the direct bandgap photoluminescence(PL) of indirect Ga_(x)In_(1-x)P alloys(0.72 ≤ x ≤ 0.74). The temperature-dependent PL shows that the energy difference between direct Γ 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 Ga_(x)In_(1-x)P 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 Γ valley. As a result, the direct band transition is enhanced in the Te-doped indirect Ga_(x)In_(1-x)P alloys. Therefore, the PL intensity of the Ga_(0.74)In_(0.26) P sample with active doping concentration of 9 × 10^(17)cm^(-3)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 5 × 10^(18)cm^(-3). From cross-section transmission electron microscopy,no large dopant clusters or other extended defects were found contributing to this degradation.