确定半导体禁带宽度的光谱方法

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Abstract：Although there are numerous optical spectroscopy techniques methods th have been used to extract thefundamental bgap asemiconductor，most them belong toone these three approaches：（1）the excitonic absorption，（2）modulion spectroscopy，（3）the most widely used Tauc-plot.The excitonic absorption is based onamany-particletheory，which isphysicallythe mostcorrectapproach，butrequires more stringent crystallnequality approprie sample preparion experimental implemention.The Tauc-plotis basedonasingle-particle theoryth neglects themany-electron effects.Modulionspectroscopyanalyzes the spectroscopy feures inthederivive spectrum，typically， thereflectance transmissionunderanexternalperturbion.Empirically，the bgap energy derived from the three approaches follow the order Eex>EMS>ETP ，where three transition energies are from excitonic absorption，modulion spectroscopy， Tauc-plot，respectively. In principle，defining Eg as the single-electron bgap，we expect Eg>Eex ，thus， Eg>ETP .In the literure， ETP is ten interpreted as Eg ，which is conceptually problemic.However，in manycases，becausethe excitonic peaksare notreadilyidentifiable，the inconsistencybetween Eg ETP becomes invisible.In this brief review，real world examples are used（1）to ilustrehow excitonic absorption feures depend sensitivelyon the sample measurement conditions；（2）to demonstre thediferences between Eex ， EMS ， kTP when they can be extracted simultaneously for one sample ； （3） to show how the popularlyadoptedTauc-plotcouldleadtomisleadingresults.Finaly，itispointedoutthiftheexcitonicabsorptionisnotobservable，the modulion spectroscopy can ten yield a more useful reasonable bgap than Tauc-plot.

Key words：semiconductor merial;bgap；excitonic absorption；modulion spectroscopy； Tauc plot CLCnumber：TN304 Document code：A DOI：10.37188/CJL.EN20240013 CSTR：32170.14.CJL.EN20240013

摘要：尽管有多种光谱技术可用来提取半导体的禁带宽度或带隙，但它们大多属于以下三种方法之一：（1）激子吸收，（2）调制光谱，（3）最广泛使用的Tauc图。（剩余30036字）