Photoacoustic investigation of semiconductors: Influence of carrier diffusion and recombination in PbTe and Si

Abstract

The photoacoustic signal of a narrow-gap semiconductor and of Si is investigated as a function of the modulation frequency through the use of a heat-transmission configuration. It is shown that in the thermally thick modulation-frequency range the signal amplitude can single out the different heating sources responsible for the photoacoustic signal. It is also shown that from the signal phase data, as a function of the modulation frequency, we can obtain the values of the surface recombination velocity and the nonradiative band-to-band recombination time.

Photoacoustic determination of the recombination velocity at the AlGaAs/GaAs heterostructure interface

“…In the past, the considerations of these mechanisms have allowed the measurement of nonradiative recombination lifetimes nr as well as the surface recombination velocity S in different semiconductor materials. [11][12][13][14][15][16] In early works these recombination mechanisms were studied in semiconductor substrates [11][12][13][14] and two-layer systems composed from different kind of samples, like semiconductor thin films on glass substrata. [15][16][17] In our case, the samples consist also in two-layer systems, where both of them are a͒ Electronic mail: vargas@uenf.br b͒ semiconductor materials, namely the GaAs substrate and the epitaxial AlGaAs layer grown over it.…”

On the Use of the Photoacoustic Technique for Monitoring the Doping Concentration Dependence of the Surface Recombination Velocity

“…In recent works, the PA technique has been used to study semiconductor surface characteristics, in particular the surface recombination velocity in different materials such as GaAs [3], CdTe [2] and Ge [5]. In [2] the authors studied the relation between the surface recombination velocity and the roughness of CdTe samples.…”

Photoacoustic investigation of doped InP using open cell configuration

“…The TDC, which is basis of design of the Open Photoacoustic Cell (OPC), is extensively used to measure both thermal and transport properties of a large number of samples such as GaAs, Si, Solar cells, CdInGeS 4 , PbTe, etc. [4,5,8]. However, the effect of doping on the thermal and transport properties of semiconductor samples has not been studied in detail, except for a few reports [9,10].…”

“…The transport properties and lifetimes of the photoexcited carriers have also been studied using PA technique. A detailed discussion of the contributions of various factors to thermal flux in semiconductors under periodic optical excitation is given by Pinto Neto et al [4,5]. In their work they studied the influence of carrier recombination and diffusion in PbTe and Si as well as thermal diffusivity of GaAs and Si.…”

“…The thermal diffusivity values of various semiconductors have been evaluated in the past by measuring PA signal as a function of modulation frequency [4,5]. The transport properties and lifetimes of the photoexcited carriers have also been studied using PA technique.…”