[18p-E101-1~7] 窒化物半導体特異構造の科学　～新機能性の発現と電子・光デバイスへの展開～

▲ [18p-E101-5] Recent progress and future of GaN and GaAs-based THz-QCL

〇Ke Wang^1,2、Li Wang²、Tsung Tse Lin²、K Fukuda²、Hideki Hirayama² (1.Nanjing Univeristy、2.RIKEN, RAP)

キーワード：quantum cascade laser, GaN, MBE

Terahertz (THz) quantum cascade lasers (QCLs) are semiconductor-based compact coherent THz sources. The operating frequency of traditional GaAs THz QCLs covers from 1 to 5.4 THz. However, the operation temperature has been limited up to 200 K for about a decade. We have revealed an extra carrier leakage channels via some high/excited energy states, which is distinct from the conventional thermally activated leakage channels and can be suppressed by engineering high-energy states. A new type asymmetric two-well indirect injection THz QCLs for breakthrough the 200 K bottleneck is proposed. More important, the potential of a new material system, GaN, for next generation THz QCL will be discussed. GaN with its 91meV phonons can in principle allow THz QCLs to operate at room temperature or even higher. They would be key coherent sources in the unexplored terahertz frequency range of 5.4-12 THz, in which GaAs THz-QCLs are not able to work due to the Reststrahlen band. Recent progress on MBE growth and fabrication of GaN THz QC structures will be discussed.