INVESTIGATING THE INFLUENCE OF THE NON-BASIC AREA ON THE PHOTOCURENT IN SEMICONDUCTOR DOUBLE-BARRIER STRUCTURES

Abstract

The investigation results of the process of longitudinal absorption of individual wavelengths in a semiconductor photodetector are presented, in the base of which, there are joining points of counteracting barriers.

The nature of the change in the n - base of the docking point position depending on the external bias voltage, the length and the intensity of the absorbed waves is revealed.

Using the obtained expression of photocurrent for p+ - n - p+ structures, in the presence of a diffusion component, the influence of the parameters of the off-base region on the modulation of the photocurrent when the external bias voltage is changed hus been studied.

For a structure with a base thickness d = 2 μk, the voltage limits are determined at which the position of the docking point of the potential barriers shifts from "0" to d. The base widths for the effective absorption of blue, green and red radiation are estimated.

The influence of the width of the off-base region on the absorption process of different waves is investigated. It is revealed that the inversion of the sign of the photocurrent does not depend on the intensity of the absorbed radiation, but on the wavelength and width of the surface layer, while the diffusion component of the photocurrent grows with increasing the wavelength. It is shown that when there is a noticeable thickness of the surface p+ layer, the indicated inversion point moves toward the larger values.

A mechanism is proposed by which, from the integrated radiation flux, it is possible to determine the intensity and length in the depth of the penetrating wave, then the parameters of the remaining waves in turn.