EBIC investigations on polar and semipolar InGaN LED structures

Polar and semipolar LED structures with InGaN quantum wells (QWs) were investigated in a scanning electron microscope (SEM) using simultaneously electron beam induced current (EBIC) and cathodoluminescence (CL). EBIC yields important information about depletion region, leakages, and the overall functionality of the pn-junction and allows to determine the diffusion length of the generated minority carriers on both sides of the pn-junction. Spectrally and spatially resolved CL measurements yield both, information about the QW quality and about centers of non-radiative recombination. EBIC measurements were carried out in top-view and in cross-section between and room temperature. The diffusion lengths measured for polar and semipolar structures prove the better crystal quality of the polar structures in terms of the higher carrier diffusion length and its increase for lower temperatures, as expected. On the semipolar structures, top-view EBIC measurements detect specific areas, where the pn-junction seems to be disturbed. The comparison of EBIC and CL measurements shows interesting correlations of the EBIC signal and the emission wavelengths of the quantum wells.

[1]  M. Hopkins,et al.  Bias dependence and correlation of the cathodoluminescence and electron beam induced current from an InGaN/GaN light emitting diode , 2014 .

[2]  Sebastian Metzner,et al.  Determination of carrier diffusion length in GaN , 2015 .

[3]  S. Chenot,et al.  Comparison between Polar (0001) and Semipolar (11\bar22) Nitride Blue–Green Light-Emitting Diodes Grown onc- andm-Plane Sapphire Substrates , 2009 .

[4]  G. E. Stillman,et al.  Electron Mobility in High‐Purity GaAs , 1970 .

[5]  A. Cavallini,et al.  Electron beam induced current, cathodoluminescence and scanning photoluminescence study of GaN layers , 2000 .

[6]  M. Hopkins,et al.  Effect of the barrier growth mode on the luminescence and conductivity micron scale uniformity of InGaN light emitting diodes , 2015 .

[7]  C. Donolato.  On the analysis of diffusion length measurements by SEM , 1982 .

[8]  T. Wunderer,et al.  I2basal plane stacking fault in GaN: Origin of the 3.32 eV luminescence band , 2011 .

[9]  Jerry R. Meyer,et al.  Band parameters for nitrogen-containing semiconductors , 2003 .

[10]  T. Mukai,et al.  Polychromatic light emission from single InGaN quantum wells grown on pyramidal GaN facets , 2005 .

[11]  S. Denbaars,et al.  Materials and growth issues for high-performance nonpolar and semipolar light-emitting devices , 2012 .

[12]  Bo Monemar,et al.  Fundamental energy gap of GaN from photoluminescence excitation spectra , 1974 .

[13]  Asif Khan.  Semiconductor photonics: Laser diodes go green , 2009 .

[14]  T. Wunderer,et al.  Three‐dimensional GaN for semipolar light emitters , 2011 .

[15]  M. Craford,et al.  Status and Future of High-Power Light-Emitting Diodes for Solid-State Lighting , 2007, Journal of Display Technology.

[16]  Colin J. Humphreys,et al.  Threading dislocation reduction in (0001) GaN thin films using SiNx interlayers , 2007 .

[17]  E. Meissner,et al.  Optimization of semipolar GaInN/GaN blue/green light emitting diode structures on {1-101} GaN side facets , 2008, SPIE OPTO.

[18]  Drew Hanser,et al.  Dislocation analysis in homoepitaxial GaInN/GaN light emitting diode growth , 2007 .

[19]  Masao Ikeda,et al.  Minority carrier diffusion length in GaN and ZnSe , 1998 .