Method for measuring carrier concentration in semiconductor quantum well

Abstract

The invention discloses a method for measuring carrier concentration in a semiconductor quantum well. The method includes steps of measuring local conductance distribution of the cross section of the semiconductor quantum well by the electric detection mode of a scanning probe microscope; setting up a numerical model capable of reflecting relation between a conducting probe-quantum well Schottky contact conductivity and carrier concentration in the quantum well; and determining parameters and carrier concentration of the quantum well of the numerical model according to the measured conductivity distribution. The method is high in spatial discrimination and has advantages in analysis of a narrow quantum well and in coupling of the quantum well, is applicable to wider carrier concentration range from non-degeneracy to degeneracy doping conditions, and has significance value for analysis of internal performances of a semiconductor photoelectric device taking a quantum well as a functional structure.

Description

technical field [0001] The invention relates to the detection of characteristic parameters of semiconductor optoelectronic functional materials, in particular to a method for obtaining carrier concentration in semiconductor quantum wells. Background technique [0002] Migrating electrons or holes, i.e. charge carriers, in semiconductors are the functional carriers of modern (opto)electronic devices. In optoelectronic devices, the transition of carriers between different energy states corresponds to the absorption and emission of photons, thereby realizing the conversion between light energy and electrical energy. In view of this, the carrier concentration and its microscopic distribution characteristics in the semiconductor functional structure are the basic information to determine the performance of the device, especially in the semiconductor quantum functional structure. Whether it is a quantum well photodetector or a quantum cascade laser, its core Structure - The carri...

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Problems solved by technology

Corresponding to this is the development of profile measurement technology based on scanning probe microscopy in recent years. This type of method extracts the carrier concentration by detecting the electronic distribution of the cross-section of functional materials, but the specific scheme or spatial resolution cannot be resolved. Quantum well scale, such as scanning capacitance microscopy (SCM); or the interpretation of measured electronic information depends on artificially adjustable parameters, which cannot achieve unidirectional extraction of carrier concentration, such as scanning distributed resistance microscopy, etc.

It should also be pointed out that for the quantum well functional structure whose response wavelength is in the infrared or even far infrared band, the subband energy gap is very narrow, which determines that the carrier binding energy in the quantum well is only below 100 millielectron volts, which is close to the heat of electrons at room temperature. Movement energy fluctuates, and most of the above-mentioned detection methods face great difficulties in terms of feasibility and measurement accuracy

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