Heterojunction laser and preparation method thereof

The invention discloses a heterojunction semiconductor laser and a preparation method thereof, a double-layer AD-type GeS stack and a double-layer rotary AB-type GeS stack are used for forming an I-type semiconductor heterojunction through transverse connection, the I-type semiconductor heterojunction is used for realizing population inversion in a laser diode, and the working current can be effectively reduced. The semiconductor laser diode sequentially comprises a lower electrode (1), a substrate (2), a lower coating layer (3), an active layer (4), an upper coating layer (5), a contact layer (6) and an upper electrode (7) from bottom to top. The selected material heterojunction is easier to achieve lattice matching, the preparation process is simpler, and the double-layer rotary AD type GeS stack and the double-layer rotary AB type GeS stack can be transversely connected to form the heterojunction only through Van der Waals force. The few-layer black phosphorene-like structures with different stacking struc