Time-Resolved Photoluminescence Measurements of In 0.15 Ga 0.85 N/In 0.015 Ga 0.985 N Quantum Wells with Si-doped Barrie
- PDF / 272,495 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 28 Downloads / 153 Views
Time-Resolved Photoluminescence Measurements of In0.15Ga0.85N/In0.015Ga0.985N Quantum Wells with Si-doped Barriers Mee-Yi Ryu, Young Jun Yu, Phil Won Yu, Eun-joo Shin1, Eunsoon Oh2, Chul Soo Sone3, Ok Hyun Nam3, and Yong Jo Park3 Dept. of Information and Communications, Kwangju Institute of Science and Technology, Kwangju 500-712, South Korea 1 Optoelectronics Group, Korea Research Institute of Standards and Science, Taejon 305-600, South Korea 2 BK21 Physics Research Division, Seoul National University, Seoul 151-742, South Korea 3 Photonics Laboratory, Samsung Advanced Institute of Technology, Suwon 440-600, South Korea ABSTRACT A systematic study of photoluminescence (PL) and time-resolved PL spectra from In0.15Ga0.85N/In0.015Ga0.985N quantum wells (QWs) with different Si doping concentration in the barriers has been carried out. As the Si doping concentration increases, the PL emission intensity was increased and the PL peak energy was blueshifted. The energy separation between the spontaneous emission (SPE) and stimulated emission (SE) peaks decrease with increasing Si doping concentration. We also observed that the slow decay time τ2 in the QWs decreases with increasing Si doping concentration, from ~ 130 ns for [Si] = 2 x 1018 cm-3 to ~ 30 ns for [Si] = 1 x 1019 cm-3. The PL emission peak shifts to lower energies with delay time after a pulsed excitation and this shift decreases with increasing Si doping concentration. The increased recombination rate, the decrease of peak shift with delay time, and the reduced separation between the SPE and SE peaks with increasing Si doping concentration are attributed to the screening of piezoelectric field by carriers originated from Si doped barriers. INTRODUCTION High-quality InGaN-based quantum well (QW) structures are of great importance because of their potential applications as light-emitting diodes (LEDs) and laser diodes (LDs), especially those operating in the blue to ultraviolet wavelength region. Many studies of InGaN-based QW properties have been reported. In particular, these studies have reported on the effects of Si doping in the barrier layers on optical [1-5], structural, and electronic properties [6,7]. The Si doped barriers make it possible to decrease carrier localization in the InGaN QW layers and/or to decrease piezoelectric potential by carriers originated from Si-doped barriers. In this study, we report the doping effects in the cw photoluminescence (PL) and time-resolved PL (TRPL) spectra of In0.15Ga0.85N/ In0.015Ga0.985N QWs with Si doped barriers. We measured the stimulated emission (SE) under a high density pulsed excitation and discuss the energy separation between the spontaneous emission (SPE) and SE peaks, decreasing from 170 to 60 meV with increasing Si doping concentration. TRPL measurements were investigated at various emission photon energies and in different time domains to study the Si doping effects on the recombination dynamics of QWs.
G9.10.1
EXPERIMENTAL DETAILS The In0.15Ga0.85N/In0.015Ga0.985N QW structures used in this study
Data Loading...
