1) Semiconductor structure 
A heterojunction is the interface that occurs between two layers or regions of dissimilar crystalline semiconductors. These semiconducting materials have unequal band gaps as opposed to a homojunction. It is often advantageous to engineer the electronic energy bands in many solid state device applications including semiconductor lasers, solar cell...
(from the article `semiconductor device`) To improve the performance of the MESFET, various heterojunction field-effect transistors (FETs) have been developed. A heterojunction is a junction ...
A region of electrical contact between two different materials. An example of a heterojunction device is a CIS photovoltaic (solar) cell, where the junction is formed by contacting two different semiconductors – cadium sulfide (CdS) and copper indium diselenide (CuInSe2)...
a PN semiconductor junction in which the two regions differ in their doping conductivities, and also in their atomic compositions
A region of electrical contact between two different materials.
heterojunction In electronics, a junction between two dissimilar semiconductor materials having different energy gaps between their valence and conduction bands.
A region of electrical contact between two different materials.