Comparative Investigation of Photoluminescence of In- and Si- doped GaN/AlGaN Multi-Quantum Wells
- PDF / 331,558 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 31 Downloads / 232 Views
Comparative Investigation of Photoluminescence of In- and Si- doped GaN/AlGaN MultiQuantum Wells W. H. Sun1, L. S. Wang1 and S. J. Chua1, 2 1 Opto- & Electronic Systems Cluster, Institute of Materials Research & Engineering, 3 Research Link, 117602, Singapore 2 Department of Electrical and Computer Engineering, National University of Singapore, 10, Kent Ridge Crescent, 119260, Singapore ABSTRACT The GaN/AlGaN multi-quantum-wells (MQWs) have been grown via metalorganic chemical vapor deposition (MOCVD). Micro-Photoluminescence (PL) measurement has been performed on non-, In- and Si- doped GaN/AlGaN multi-quantum-well samples in the temperature ranges of 90-300 K. In the non-doped GaN/AlGaN multi-quantum-wells we observed the free exciton peak at 3.4587 eV at 90 K. Other exciton related peaks are located at 3.4346, 3.4177, 3.394, 3.3129eV, which are probably associated with the strongly localized excitons involving the defects. In In-doped GaN/AlGaN MQWs, the free exciton peaks have a slight red-shift from 3.4712 to 3.4629 eV, but the PL intensities become stronger with increasing trimethylindium (TMIn) flow from 10.6 to 42.6-µmol/min. With Si-doping in the well layers, photoluminescence exhibits an envelope of exciton bands ranged from 3.4796eV (free exciton) to 3.43915eV. The excitonic peaks in the bands vary in intensity and position with sample temperature. In addition, we have also observed the LO phonon replica of AlGaN interacted by the laser line due to the resonance effect. INTRODUCTION Major developments in wide band-gap group III nitrides have recently led to the commercial production of high-brightness blue/green/amber light-emitting diodes (LEDs) and to the realization of room-temperature (RT) violet laser light emission under pulsed and continuous operation [1-3]. Recently, it has been found that the photoluminescence (PL) intensity of GaN films at room temperature was greatly enhanced by the isoelectronic In-doping method during the growth, which was more than 30 times stronger in PL magnitude than that of non-doped samples [4]. Several groups have reported positive effects of indium on the improvements of optical properties of GaN films grown by metalorganic chemical vapor deposition (MOCVD) [5] and molecular beam epitaxy (MBE) [6,7]. A great deal of research has been conducted on GaN/AlGaN multiquantum well structures on the influence of well widths and piezoelectric field due to the mismatch-induced strain on the optical properties [9-12]. Impurity-doping in active layers is one of many interesting topics when the structural materials are grown for fabricating the light emission device above. However, there are few reports on the indium and silicon impurity-doping into well layers in GaN/AlGaN multiquantum well structures. In the present F8.26.1 Downloaded from https://www.cambridge.org/core. Gothenburg University Library, on 04 Feb 2020 at 19:01:06, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1557/PROC-719-F8.26
study, we will i
Data Loading...
