The design and simulation of p-type Si/SiGe Terahertz quantum cascade lasers

• This paper gives a new design for Si/SiGe Terahertz quantum cascade lasers.
• The upper state lifetime is prolonged to 32 ps compared to previous work of 23 ps.
• The optical gain is similar to the BTC structure but simple for material growth.
• This paper is organized clearly, giving a fundamental demonstration of our design.

To prolong upper state lifetime in p-type Si/Si1−xGex Terahertz quantum cascade lasers, a new active region is designed in this work. Using 6×6 k·p theory, the eigenvalues and wavefunctions of heavy holes and light holes are firstly calculated in a single SiGe quantum well. The design in the active region of this THz Si/Si1−xGex quantum cascade lasers is then investigated. This work presents a SiGe quantum cascade laser with about 6.84 THz emission in the diagonal transition. The calculations show that about 32 ps of the upper state lifetime and about 9 cm−1 of optical gain are obtained, which are enhanced when compared to previous designs.