By integrating a resonant tunneling diode with a 1.2 μm-thick slightly doped n-type GaAs layer in a three-barrier, two-well resonant tunneling structure, the resonant tunneling of photo-excited holes exhibits a value of peak-to-valley current ratio (PVCR) as high as 36. A vast number of photo-excited holes generated in this 1.2 μm-thick slightly doped ntype GaAs layer, and the quantization of hole levels in a 23nm-thick quantum well on the outgoing side of hole tunneling out off the resonant tunneling diode which greatly depressed the valley current of the holes, are thought to be responsible for such greatly enhanced PVCR.朱汇（中国科学院半导体研究所,超晶格国家重点实验室,北京,100083）郑厚植（中国科学院半导体研究所,超晶格国家重点实验室,北京,100083）李桂荣（中国科学院半导体研究所,超晶格国家重点实验室,北京,100083）谭平恒（中国科学院半导体研究所,超晶格国家重点实验室,北京,100083）甘华东（中国科学院半导体研究所,超晶格国家重点实验室,北京,100083）徐平（中国科学院半导体研究所,超晶格国家重点实验室,北京,100083）张飞（中国科学院半导体研究所,超晶格国家重点实验室,北京,100083）章昊（中国科学院半导体研究所,超晶格国家重点实验室,北京,100083）肖文波（中国科学院半导体研究所,超晶格国家重点实验室,北京,100083）孙晓明（中国科学院半导体研究所,超晶格国家重点实验室,北京,100083）