In one embodiment, a heterojunction structure includes a first substrate; a second substrate comprising an electrode pad, the second substrate joined to the first substrate by an adhesive layer interposed between the first and second substrates, the first substrate and the adhesive layer having a via hole penetrating therethrough to expose a region of the electrode pad; a connection electrode disposed in the via hole and contacting the electrode pad; and an insulation layer electrically insulating the connection electrode from the first substrate. One of the first and second substrates has a thermal expansion coefficient different than a thermal expansion coefficient of the other of the first and second substrates, and at least one of the adhesive layer or the insulation layer comprises an organic material.