Two mechanisms of blueshift of edge emission in InGaN-based epilayers and multiple quantum wells

We present the results of a comparative photoluminescence (PL) study of GaN and InGaN-based epilayers, and InGaN/GaN multiple quantum wells (MQWs). Room-temperature PL spectra were measured for a very broad range of optical excitation from 10 mW/cm2 up to 1 MW/cm2. In contrast to GaN epilayers, all In-containing samples exhibited an excitation-induced blueshift of the peak emission. In addition, the blueshift of the emission in the InGaN epilayers with the same composition as the quantum well was significantly smaller. The comparison of the blueshift in the “bulk” InGaN and in the MQWs allowed us to separate two different mechanisms responsible for this effect: (i) filling of the localized states in In-rich areas and (ii) screening of the polarization electric field in strained MQW structures.

[1]  Shuji Nakamura,et al.  Luminescences from localized states in InGaN epilayers , 1997 .

[2]  S. Nakamura,et al.  InGaN-Based Multi-Quantum-Well-Structure Laser Diodes , 1996 .

[3]  Shuji Nakamura,et al.  The Blue Laser Diode: GaN based Light Emitters and Lasers , 1997 .

[4]  R. J. Shul,et al.  GAN : PROCESSING, DEFECTS, AND DEVICES , 1999 .

[5]  M. Shur,et al.  Polarization Effects and UV Emission in Highly Excited Quaternary AlInGaN Quantum Wells , 2001 .

[6]  Oliver Ambacher,et al.  Determination of the Al mole fraction and the band gap bowing of epitaxial AlxGa1−xN films , 1997 .

[7]  Thomas George,et al.  Vertical–cavity stimulated emission from photopumped InGaN/GaN heterojunctions at room temperature , 1994 .

[8]  S. Denbaars,et al.  Impact of Internal Electric Field and Localization Effect on Quantum Well Excitons in AlGaN/GaN/InGaN Light Emitting Diodes , 2001 .

[9]  David Vanderbilt,et al.  Spontaneous polarization and piezoelectric constants of III-V nitrides , 1997 .

[10]  Petr G. Eliseev,et al.  BLUE TEMPERATURE-INDUCED SHIFT AND BAND-TAIL EMISSION IN INGAN-BASED LIGHT SOURCES , 1997 .

[11]  Isamu Akasaki,et al.  Quantum-Confined Stark Effect due to Piezoelectric Fields in GaInN Strained Quantum Wells , 1997 .

[12]  M. Osiński,et al.  Optical and Electrical Characteristics of Single-Quantum-Well InGaN Light-Emitting Diodes , 1996 .

[13]  W. Brinkman,et al.  Electron-hole liquids in semiconductors , 1973 .

[14]  Atsuhiro Kinoshita,et al.  Determination of photoluminescence mechanism in InGaN quantum wells , 1999 .

[15]  Robert W. Martin,et al.  Origin of Luminescence from InGaN Diodes , 1999 .

[16]  Kazumi Wada,et al.  Exciton localization in InGaN quantum well devices , 1998 .

[17]  A. V. Dmitriev,et al.  The rate of radiative recombination in the nitride semiconductors and alloys , 1999 .

[18]  Kevin F. Brennan,et al.  Quantum Semiconductor Structures , 1992 .

[19]  G. Coli,et al.  Spontaneous polarization and piezoelectric field in G a N / A l 0.15 Ga 0.85 N quantum wells: Impact on the optical spectra , 2000 .

[20]  Shuji Nakamura,et al.  Recombination dynamics of localized excitons in In 0.20 Ga 0.80 N- In 0.05 Ga 0.95 N multiple quantum wells , 1997 .