Влияние квантового магнитного поля на разогрев носителей заряда в чистом Ge

The results of an experimental study of charge-carrier heating by an electric field E in pure n - and p -type germanium samples in a quantizing magnetic field H , at E ⊥ H and under carrier photoexcitation conditions, are considered in detail. The results obtained are in qualitative agreement with the predictions of the theory of charge-carrier capture in crossed electric and magnetic fields.

The charge carrier capture–emission process – the main source of the low-frequency noise in homogeneous semiconductors

The possibility of determination of the number of localized capture centers of defects (relaxators) that cause low-frequency noise in a particular frequency range has been investigated. Here it is shown that a minimum number of relaxators is needed to generate 1/f type low-frequency noise only when relaxation times are arbitrarily distributed one-by-one in every two-octave range. The expression for estimation of the low-frequency noise level of the sample under test is presented. The presented expression for 1/f noise explains not only the noise level dependence both on the frequency and number of defects in the sample but also the observed noise intensity dependence on the mobility of free charge carriers. It is shown that the main source that causes low-frequency noise in homogeneous semiconductors is the charge carrier capture–emission process.

A DETAIL ANALYSIS OF ELECTRICAL AND OPTICAL FLUCTUATIONS OF GREEN LIGHT-EMITTING DIODES BY CORRELATION METHOD

A detail analysis of electrical and optical fluctuations of large power (1 W) green light-emitting diodes (LEDs) is presented. Special attention was directed to measurement and interpretation of correlation coefficient between electrical and optical fluctuations. The correlation coefficient was measured not only over frequency range from 10 Hz to 20 kHz, but also in every one-octave frequency band by using digital filters. It is shown that correlated part of electrical and optical fluctuations for investigated green LEDs is related with random potential fluctuations of parameters of quantum well due to charge carrier capture by the defects in the active layer, while uncorrelated part of electrical noise is caused by parallel leakage channel which resistance is many times higher than that of p-n junction.

A Novel Method for Contactless, Non Destructive Investigation of Semi Conductor Structures in the SEM.

It is known that scanning a focussed laser beam across the surface of a semi conductor wafer, can produce a photon induced voltage (PIV) at electrically active sites. This technique depends upon the incident photons inducing charge carriers, both electrons and holes, on or just below the surface of the semi conductor. These charge carriers drift through the device until they are captured by a defect, at which stage they accumulate, producing a voltage at the surface. These voltages are only associated with a charge carrier capture site, which means that a voltage build up only occurs at a defect. This PIV technique has been used for contactless imaging of semiconductor wafers, allowing easy identification of electrically active sites such as crystallographic defects, imperfections and inhomogenieties on or just below the surface [1,2].Nothing in the above mechanism excludes the use of an electron beam to induce charge carriers and produce an electron induced voltage (EIV).