Glossary entry

Auger recombination

A non-radiative carrier recombination process in which the energy of an electron–hole pair is transferred to a third carrier rather than emitted as a photon. The dominant non-radiative loss in long-wavelength III–V semiconductor lasers.

Lasers & gain Optics fundamentalsUpdated October 2026

In Auger recombination, an electron and hole recombine without emitting a photon; instead, the released energy is transferred to a third carrier (electron or hole), promoting it to a higher state. The energy then thermalizes via phonon emission, ultimately becoming heat.

The Auger recombination rate scales as the third power of carrier density:

R_{Auger} = C n^{3} (intrinsic, n = p),

or more generally $R = C_{n} n^{2} p + C_{p} n p^{2}$ for the electron-Auger and hole-Auger processes. $C$ is the Auger coefficient with units of cm $^{6}$ /s.

Typical Auger coefficients at 300 K:

Material	$C$ (cm $^{6}$ /s)	Emission $λ$
GaAs (bulk)	$\sim 1 \times 10^{- 30}$	870 nm
AlGaAs ( $λ \approx 850$ nm)	$1 - 5 \times 10^{- 30}$	750 – 850 nm
InGaAs/GaAs QW	$\sim 5 \times 10^{- 30}$	980 nm
InGaAsP/InP (bulk, 1.55 μm)	$10^{- 29}$ to $10^{- 28}$	1300 – 1550 nm
InGaAlAs/InP MQW (1.55 μm)	$\sim 5 \times 10^{- 29}$	1550 nm
InGaAsSb (mid-IR, 2 – 3 μm)	$\sim 10^{- 27}$	2 – 3 μm

Auger recombination becomes severe as the bandgap decreases. The energy released by electron–hole recombination becomes resonant with available carrier transitions, dramatically increasing the matrix element. This is a leading reason why:

InP-based lasers have lower $T_{0}$ ( $\sim 50$ – $70$ K) than GaAs-based lasers ( $\sim 120$ – $160$ K). See characteristic temperature
Mid-IR semiconductor lasers ( $\geq 2$ μm) operate inefficiently at room temperature; quantum cascade lasers were developed in part to bypass Auger by using unipolar (electron-only) transitions
Threshold current density scales steeply with temperature in long-wavelength lasers

The strong temperature dependence of Auger ( $C (T) \approx C_{0} \exp (- E_{a} / k T)$ in some models) is what makes InGaAsP devices particularly sensitive to active-region heating. Pulsed measurement is often required for accurate parameter extraction (see Pulsed vs Continuous-Wave LIV Measurement).