Photocurrent Investigation on a Graded Heterojunction

Abstract

The barrier height EB of a graded heterojunction as a function of the position is determined from photocurrent, Iph, and capacitance–voltage measurements on LPE grown anisotype heterostructures. The reliability of a theoretic relation obtained between Iph and EB is confirmed investigating the temperature dependence Iph(T). Using the capacitance and photocurrent–voltage measurements the dependence EB(W) (W width of the space charge region) is concluded. As a result, a heterotransition graduated in the range of about 150 nm with an averaged gradient ΔEB/Δz = 1 mV/nm is obtained. However, the barrier height is a complicated function of the position.

Photo-emf in Parabolic Graded-Gap Semiconductors

“…Semiconductors of variable composition (graded band-gap semiconductors) have been quite attractive for application to various optoelectronic light-emitting and photoreceiving devices already for a long time [1][2][3][4][5]. The coordinate dependence of the bandgap and also of some other parameters of semiconductors leads to many interesting features in the photoelectric properties of graded band-gap semiconductors (GGS).…”