Indium Nitride (InN) Evidence of Narrow Fundamental Band Gap  NSM Archive
Band structure and carrier concentration
Basic ParametersBand structure
Intrinsic carrier concentration
Effective Density of States in the Conduction and Valence Band
Temperature Dependences
Dependences on Hydrostatic Pressure
Band Discontinuities at Heterointerfaces
Effective Masses and Density of States
Donors and Acceptors
Evidence of Narrow Fundamental Band Gap.
Absorption, emission and excitation spectra
Structure Analysis
Electronic structure (new dates)
Teoretical Calculations
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Evidence of Narrow Fundamental Band Gap.
Absorption, emission and excitation spectra.
InN, Wurtzite (hexagonal). Photoluminescence spectra for samples
with different electron concentrations: n ~ 9x10^{18} cm^{3} (MOMBE grown sample CUI489); n ~1.2x10^{19} cm^{3} (PAMBE grown sample W251). The inset shows the spectra for the sample with electron concentrations of n ~ 9x10^{18} cm^{3} (CUI489): 1  photoluminescence; 2  optical absorption; 3  photoluminescence excitation. Davydov et al. Phys. Stat. Solidi (b) 229 (2002a), R1 Contact authors: Valery Yu. Davydov Remark. It was the first observation of edge photoluminescence in nearinfrared region in singlecrystalline InN . 

InN, Wurtzite (hexagonal). Photoluminescence spectra of
InN layers with different carrier concentrations. 1  n = 6x10^{18} cm^{3} (MOCVD grown sample); 2  n = 9x10^{18} cm^{3} (MOMBE grown sample); 3  n = 1.1x10^{19} cm^{3} (MOMBE grown sample); 4  n = 4.2x10^{19} cm^{3} (PAMBE grown sample). Solid lines show the theoretical fitting cures based on a model of interband recombination in degenerated semiconductors. As a result, the true value of InN band gap E_{g}~0.7 eV was established. Davydov et al. Phys. Stat. Solidi (b) 230 (2002b), R4 Contact authors: Valery Yu. Davydov 

InN, Wurtzite (hexagonal). Calculated shift of optical absorption edge
due to the BursteinMoss effect in ntype InN (solid line) vs. electron
concentration. The parabolic conduction band with an effective electron mass of m*=0.1 m_{o} is assumed. Open circles present the values ( E_{g} + E_{F}) estimated from the fitting of photoluminescence spectra. Davydov et al. Phys. Stat. Solidi (b) 230 (2002b), R4 

Inrich In_{x}Ga_{1x}N alloys. Photoluminescence
spectra of layers with different compositions at T=77 K. The inset shows the semilog photoluminescence spectra of most perfect alloys and the fitting cures of the spectra based on a model interband recombination in degenerated semiconductors . Davydov et al. Phys. Stat. Solidi (b) 230 (2002b), R4 Remark. It was the first observation of edge photoluminescence in singlecrystalline inrich In_{x}Ga_{1x}N alloys (0.36<x<1). 


In_{x}Ga_{1x}N alloys. The E_{g} valus
estimated for Inrich alloys (full blue circles, this work), and positions
of photoluminescence band maxima in Garich alloys (open symbols) as a function
of In_{x}Ga_{1x}N composition. Composition dependence of the band gap (solid line) is fitted by equation E_{g}(x)=3.493  2.843x  bx(1x) with a bowing parameter b=2.5 eV. Refs.: M. H. Kim, J. K. Cho et al., Phys. Stat. Sol.(a) 176, 269 (1999); K. P. O'Donnell et al., J. Phys. Condens. Matt. 13, 6977 (2001) ; A. Klochikhin, A. Reznitsky et al., Nanostructures: Physics and Technology, Ioffe Institute, St. Petersburg 2001, p.554. Davydov et al. Phys. Stat. Solidi (b) 230 (2002b), R4 
InN, Wurtzite (hexagonal). (a) Optical absorption (300 K),
photoluminescence (300 K), and PR (77 K) spectra. This sample is undoped
with roomtemperature electron concentration of n=5.48x1018 cm3.
The spike on the PR spectrum at 0.97 eV is an artifact due to the light
source used in the PR measurement. (b) Roomtemperature mobility, photoluminescence peak energy (300 and 12 K), and the critical energy determined by PR (77 K) as a function of freeelectron concentration n. The sample with n=1x1019 cm3 (indicated by a broken arrow) is the Ritsumeikan sample. Wu J., Walukiewicz W. et al. Appl. Phys. Lett. 80 (2002a) 3967 Contact authors: W. Walukiewicz  
InN, Wurtzite (hexagonal). (a) Photoluminescence spectra vs.
temperature (the sample with roomtemperature electron concentration
of 5.48x10^{18} cm^{3} . The spectra are normalized to
a constant peak height. (b) Photoluminescence peak energy and photoluminescence integrated intensity (log scale) vs. temperature. The line through the peak energy data is a guide for the eye. Wu J., Walukiewicz W. et al. Appl. Phys. Lett. 80 (2002a) 3967  
In_{1x}Ga_{x}N alloys. (a) Photoluminescence
signal taken at room temperature (solid line) and 11 K (dashed
line) for samples with Ga atomic fraction x ranging from 0% to 50%.
All curves are normalized to equal height and offset vertically for clarity.
(b) Roomtemperature absorption coefficient squared as a function of photon energy. Wu J., Walukiewicz W. et al. Appl. Phys. Lett. 80 (2002b) 4741 Contact authors: W. Walukiewicz Remark. An anomalous 'blue' shift
of the photoluminescence peak for InN and Inrich In_{1x}Ga_{x}N
alloys with increasing temperature observed by Wu
J., Walukiewicz W. et al. (2002 a,b) does not agree with normal
'red' shift for InN observed by Davydov
et al. Phys. Stat. Solidi (b) 234 (2002c), 787.  
In_{1x}Ga_{x}N alloys. Photoluminescence
peak energy and band gap determined by optical absorption vs composition.
Some previously reported data on the Garich side are also shown (Refs.6
and 7). All data are taken at room temperature unless otherwise noted.
The solid curve shows the fit to the band gap energies (abs and PT) by the equation E_{g}(x)=3.42x+ 0.77(1x)  bx(1x) with a bowing parameter b=1.43 eV. The dashed curve is the fit to the band gap energies on the Garich side assuming a band gap of 1.9 eV for InN. Inset: Photoluminescencepeak energy plotted against absorption edge energy. The solid line is a leastsquare fit to experimental data on the Garich side adopted from Ref. 8. The dashed straight line shows the relation when the Stokes shift is zero. Ref.6  Pereira S. et al., Appl. Phys. Lett. 78, (2001) 2137; Ref.7  Shan W. et al. J. Appl. Phys. 84, (1998) 4452; Ref.8  O'Donnell K.P. et al., Phys. Status Solidi B 216, (1999) 141. Wu J., Walukiewicz W. et al. Appl. Phys. Lett. 80 (2002b) 4741 

In_{x}Ga_{1x}N alloys. The relation between In content
and the bandgap energy. [2]  Osamura, K., Naka, S., and Murakami, Y., J. Appl. Phys. 46, (1975), 3432. [3]  Puychevrier N. & Menoret M., Thin Solid Films 36, (1976), 141. [4]  Tansley T. L. & Foley C. P., J. Appl. Phys. 59, (1986), 3241. [7]  Matsuoka T., Tanaka H., Sasaki T. & Katsui A., Proc. of the Sixteenth International Symposium on GaAs and Related Compounds, Karuizawa, Japan, 2529 September 1989, Institute of Physics, Bristol (1990), p.141. Matsuoka et al. Appl. Phys. Lett. 81, (2002) 1246 Contact authors: T. Matsuoka 

InN, Wurtzite (hexagonal). Roomtemperature absorption edge vs electron
concentration. The solid line is the calculated band gap assuming a nonparabolic (E_{P}=10 eV) dispersion for the conduction band and including the bandrenormalization effects. The dotteddashed line is the same calculation but without including the bandrenormalization effects. The dotted line is the result of a calculation assuming a parabolic (m*=0.07m_{o}) conduction band. Inset: absorption (squared) curves for four samples with different freeelectron concentrations (in cm^{3}). Wu J., Walukiewicz W., Shan W. et al. Phys. Rev. B 66 (2002c), 201403 Contact authors: W. Walukiewicz 

InN, Wurtzite (hexagonal). 
In_{x}Ga_{1x}N alloys. (a) Photoluminescence
spectra of films vs. In concentrations x. T=77 K. (1)  x = 0.370.47; (2)  x = 0.53; (3)  x = 0.63; (4)  x = 0.68; (5)  x = 0.73; (6)  x = 0.94; (7)  x = 0.97; (8)  x = 1.00. (b) Absorption spectra of In_{x}Ga_{1x}N films vs. photon energy. The temperature T=300 K (high indium composition region). Hori et al. Phys. Stat. Sol. (b) 234 (2002) 750 Contact authors: M. Hori & Y. Nanishi 

In_{x}Ga_{1x}N alloys. Luminescence peak positions
of catodoluminescence and photoluminescence spectra vs. concentration
x. The plots of luminescence peak positions can be fitted to the curve E_{g}(x)=3.48  2.70x  bx(1x) with a bowing parameter of b=2.3 eV Ref.1  Wetzel., Appl. Phys. Lett. 73, 73 (1998). Ref.2  V. Yu. Davydov., Phys. Stat. Sol. (b) 230, R4 (2002). Ref.3  O’Donnel., J. Phys .Condens. Matt. 13, 1994 (1998). Hori et al. Phys. Stat. Sol. (b) 234 (2002) 750 

InN. PL spectra. The temperature dependence of the resonance
at the position of the Fermi edge for an InN layer doped with n=8x10^{17}cm^{3}.
Basically two contributions can be seen in PL: One at the position of the renormalized gap (weak shoulder at ~650meV) and one at the position of the Fermi edge (~730meV) which is interpreted as a Mahan exciton. Feneberg et al., Phys. Rev. B 77 (2008), 245207 Contact authors: Klaus Thonke & Martin Feneberg 

InN. A series of reflectance spectra recorded at different temperatures
is shown for a sample with n=3x10^{18}cm^{3}. Feneberg et al., Phys. Rev. B 77 (2008), 245207 Contact authors: Klaus Thonke & Martin Feneberg These measurements confirm the low bandgap values of ~ 0.7 eV for InN at low temperature. 
Structure Analysis of InN Film Using Extended XRay Absorption Fine Structure Method.
Remarks  Referens  
Atomic distance of InN d_{InN} 
2.15 A  In Kedge EXAFS oscillation, film grown on sapphire using MBE 
Miyajima T. et al. (2002) 
Atomic distance of InIn d_{InIn} 
3.53 A  In Kedge EXAFS oscillation, film grown on sapphire using MBE aaxis lattice constant a = 3.536 A (Xray diffraction) caxis lattice constant c = 5.701 A 
The InN atomic bonding has an ideal property of sp^{3} hybridization in InN film, which has a direct bandgap energy of 0.8 eV, since the radial structure functions around the In atoms obtained by EXAFS was close to that obtained in a simulation based on the ideal structure of Wurtzite (hexagonal) and ZincBlende InN [Miyajima et al. Phys. Stat. Sol. (b) 234(3) (2002), 801]
Contact authors: T. Miyajima
Measuring electronic structure using electron energy loss spectroscopy
InN, Wurtzite (hexagonal). Solid line: Nitrogen Kedge from EELS measurements Dashed line: calculated nitrogen N 2p partial DOS. To eliminate small energy drift in STEM the spectrum is aligned with corresponding xray absorption data (LawniczakJablonska K. et al., Appl. Phys. Lett. 70 (1997) 2711). The DOS calculations are aligned to EELS by displacing the primary peak to 401.8 eV for better comparison of the remaining features. The measured spectrum of the nitrogen K edge is in excellent agreement with calculated N 2p partial DOS of conduction band on the relative positions of major peaks. Mkhoyan et al. Appl. Phys. Lett. 82 (2003) 1407 Contact authors: K. Andre Mkhoyan 

InN, Wurtzite (hexagonal). Single scattering distribution obtained
from lowloss EELS. The dashed line is calculated In 5p partial DOS of the conduction band convoluted with In 4d valence states. Measurements coupled with calculations indicate that these highly localized In 4d deep valence band states in wurtzite InN are 16.3±0.5 eV below the minimum of the conduction band. If we adopt the measured value of band gap of about 0.8 eV then the In 4d deep valence band states should be 15.5±0.5 below the top of the valence. From lowloss EELS, the position of the bulk plasmonloss peak at 15.5 eV and strong interband transitions with energy 6.2 eV are also obtained. Mkhoyan et al. Appl. Phys. Lett. 82 (2003) 1407 
Teoretical Calculations.
InN, Wurtzite (hexagonal). Energy band structure Solid lines: Density Functional Theory in Local Density Approximation (DFTLDA) Dashed lines: including quasiparticlecorrections. Bechstedt et al. Phys. Stat. Sol. (a) 195 (2002) 628 
Electronic archive: Physical Properties of Semiconductors