GaN - Gallium Nitride

Mobility and Hall Effect

Wurtzite GaN.
GaN is an extrinsic n-type semiconductor, p-type material does not seem achievable. Above room temperature transport is predominantly determined by polar-optical scattering and at lower temperatures by impurity scattering. Crystals with n larger than 8x1018cm-3 show metallic conduction with no appreciable variation in n or μn between 10 and 300 K.
    Remarks Referens
Conductivity σ 6÷12 Ω-1 cm-1 300 K ; n ~= 1017 cm-3, undoped layers grown by vaporphase technique on sapphire Ilegems (1972); Ilegems & Dingle (1973); Crouch et al. (1978)
Mobility electrons    μn =< 440 cm2 V-1 · s -1 300 K ; purest material, n ~= 1017 cm-3 Ilegems (1972); Ilegems & Dingle (1973); Crouch et al. (1978)
GaN, Wurtzite sructure. Electron Hall mobility vs. temperature for two samples
Ilegems & Montgomery (1973).
GaN, Wurtzite sructure. Electron Hall mobility versus temperature for different doping levels and different degrees of compensation θ = Na/Nd.
1 - unintentionally doped [Nakamuraetal.(1992)];
2 - Nd = 3.1x 1017 cm-3, θ < 0.03 [Gotz et al. (1996)];
3 - Nd = 1.1 x 1017cm-3, θ ~= 0.3 [Gotz et al. (1996)];
4 - Nd = 2.3 x 1017 cm-3, θ < 0.04 [Gotz et al. (1996)];
5 - Nd = 7.4 x 1017 cm-3, θ < 0.01 [Gotz et al. (1996)];
6 - The concentration of introduced Si Ndo = 2 x 1019cm-3 [Gotz et al. (1996)].
The calculations of electron mobility vs. the temperature for different doping levels and compensation ratios see in Chin et al. (1994).
GaN, Wurtzite sructure. The calculated electron drift (solid curves) and Hall (dashed curves) mobility versus carrier concentration at different compensation ratios θ:
1 - θ = 0;     2 - θ = 0.15;    
3 - θ = 0.30;     4 - θ = 0.45;
5 - θ = 0.60;     6 - θ = 0.75; 7 - θ = 0.90.
T = 77 K. Experimental data are taken from four different papers
Chin et al. (1994).
GaN, Wurtzite sructure. The calculated electron drift (solid curves) and Hall (dashed curves) mobility versus carrier concentration at different compensation ratios θ:
1 - θ = 0;     2 - θ = 0.15;    
3 - θ = 0.30;     4 - θ = 0.45;
5 - θ = 0.60;     6 - θ = 0.75; 7 - θ = 0.90.
T = 300K. Experimental data are taken from four different papers
Chin et al. (1994).
GaN, Wurtzite sructure. Hole Hall mobility versus temperature. Hole concentration at T= 300 K and p ~= 4 x 1012 cm-3
Rubin et al. (1994).
GaN, Wurtzite sructure. Hole Hall mobility versus hole concentration GaN at T = 300 K
Gaskill et al. (1995).
Zinc Blende GaN (cubic)
GaN, Zinc Blende (cubic). Electron Hall mobility versus temperature for different doping levels (cubic GaN). Electron concentration at room temperature:
1 - 1.5 x 1018 cm-3;
2 - 1.3 x 1019 cm-3,
3 - 2.8 x 1019 cm-3;
4 - 1.5 x 1020 cm-3,
5 - 3 x 1020 cm-3.
Kim et al. (1994).
GaN, Zinc Blende (cubic). The electron Hall mobility at three temperatures vs. the carrier concentration.
T (K): 1-80; 2-150; 3-300.
Kim et al. (1994).
GaN, Zinc Blende sructure. The hole Hall mobility vs the temperature (two samples). The hole concentration p = (0.6 - 1) x 1013 cm-3 at T= 300K .
As et al. (1996).

Two-Dimensional Electron Gas Mobility at AlGaN/GaN interface

GaN. Electron Hall mobility and sheet concentration vs. temperature for two-dimensional gas in AlGaN/GaN heterostructure grown on 6H-SiC substrate.(the sample as in next Figure).
Gaska et al. (1998).
GaN. Measured (open circles) and calculated (solid lines) Hall mobility versus temperature (the sample as in previous Figure). Electron scattering processes by optical and acoustic phonons, piezoelectric, and impurity scattering were taken into account.
Gaska et al. (1998).
GaN. Electron Hall mobility versus temperature for two AlGaN/ GaN heterostructures (1,2) and related GaN layers (1',2' ) grown on sapphire. Electron concentrations in the two-dimensional electron gas and GaN layers at room temperature are:
1: n2deg ~= 7 x 1012 cm-2,       2: n2deg ~= 7.5 x 1012 cm-2,
1': n ~= 7 x 1016 cm-3,       2': n ~= 1.5 x 1018 cm-3
Dziuba et al. (1997).