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在ＧａＡｓ／ＡｌＡｓ（１０ｎｍ／２ｎｍ）弱耦合掺杂超晶格Ｉ－Ｖ曲线的第一个平台上，我们首先观测到了直流偏压下的室温微波振荡．观测到的最高振荡频率可达１４２ＭＨｚ．这种由级联隧穿引起的振荡在测试温度范围１４～３００Ｋ内始终存在．经分析发现：由于垒层仅有２ｎｍ，电子隧穿通过垒层的几率很高，相比之下，电子越过势垒而产生的热离子发射电流要小得多．在温度低于３００Ｋ时，超晶格内的纵向输运机制是级联共振隧穿和声子辅助隧穿．这是室温仍然能观测到自维持振荡的主要原因．由于实现振荡所施加的偏压比较低（在室温下偏压范围大约为０．５～２Ｖ），有利于抑制室温下通过Ｘ谷的热离子发射电流．
At the first platform of the I-V curve of the weakly coupled doped superlattice of GaAs / AlAs (10nm / 2nm), we first observed the microwave oscillation at room temperature under DC bias. The highest observed oscillation frequency up to 142MHz. This oscillation caused by cascade tunneling always exists within the test temperature range of 14 ~ 300K. The analysis shows that, because the barrier is only 2 nm, the probability of electrons tunneling through the barrier is high, in contrast to the much smaller thermionic emission current generated by electrons crossing the barrier. At temperatures below 300K, the mechanism of longitudinal transport within the superlattice is cascade resonant tunneling and phonon-assisted tunneling. This is the main reason why self-sustaining oscillations can be observed at room temperature. Since the bias applied to achieve oscillation is relatively low (about 0.5 to 2 V at room temperature), it is advantageous to suppress the emission of thermionic ions through the X-valley at room temperature.