Chen, Y.-H.Y.-H.ChenHsu, K.-T.K.-T.HsuChen, K.-L.K.-L.ChenJan, G.-J.G.-J.JanHAO-HSIUNG LIN2020-06-112020-06-111994https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028422613&doi=10.1143%2fJJAP.33.2448&partnerID=40&md5=c3525375d217c54971f5c3ab5849919cUsing contactless photoreflectance at 300 K we have characterized two InAlAs/InGaAs heterojunction bipolar transistor structures grown by molecular beam epitaxy. The spectra from the InAlAs and InGaAs interface can be accounted for on the basis of a triangular potential well which confined two-dimensional electron gas. A detailed lineshape fit makes it possible to evaluate the Fermi energy, and hence the two-dimensional electron gas concentration. Furthermore, other important parameters of the system, such as built-in electric fields and In composition, can be evaluated. © The Japan Society of Applied Physics.[SDGs]SDG7Composition effects; Electric field effects; Electron transitions; Excitons; Heterojunctions; Interfaces (materials); Molecular beam epitaxy; Semiconducting aluminum compounds; Semiconducting gallium arsenide; Semiconducting indium compounds; Semiconductor device structures; Semiconductor growth; Indium aluminum arsenide; Indium gallium arsenide; Photoreflectance; Two dimensional electron gas; Bipolar transistorsjournal article10.1143/JJAP.33.24482-s2.0-0028422613