Au/graphene/n-InP Schottky barrier diode (SBD) was fabricated by the use of spray pyrolysis technique with a monolayer graphene interlayer, and the temperature dependent characteristics was performed in a wide temperature range from 60 to 300 K with steps. The Au/GR/n-InP SBD exhibited excellent rectifying behavior however barrier height (Φ b0 ) of the device increased with increasing temperature while ideality factor (n) and series resistance (R s ) decreased. The strong temperature dependency of SBH and the deviation from theoretical value of Richardson constant clarified by considering a Gaussian distribution model of the SBH which was caused by the BH inhomogeneities. The mean BH F b0 of 0.94 and 0.59 eV was estimated with the standard deviation of 0.011 and 0.004 eV attributed to the presence of a double GD of SBD. The modified Richardson plots gave mean BH value of 0.98 and 0.70 eV and the Richardson constant values of 8.10, 13,38 A K −2 cm −2 was very close to its theoretical value of 9.4 A K −2 cm −2 . These results yields that carrier transport mechanism of Au/GR/n-InP SBD can be clarified by Thermionic-emission-diffusion (TED) mechanism with a double Gaussian distribution of the SBHs. In addition, the I-V characteristics of SBD under dark and light ambiance indicates that Au/graphene/n-InP is strongly dependent on the light effect. Thus, we can conclude that graphene/n-InP device is a potential candidate for photovoltaic systems. Moreover, the UV-vis spectroscopy of the graphene film exhibit a strong absorption as A=9.45% compared to the literature, that is, Au/GR/n-InP SBD grown by spray pyrolysis has excellent optical properties for optoelectronic applications.

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Öz Schottky engel diyotları n-tipi InP (100) yarıiletkeni kullanılarak elde edildi. Ohmik kontaklar In metali buharlaştırıldıktan sonra 320 o C'de ve N2 ortamında tavlanarak yapıldı. Schottky kontakları 0,5 mm çapında ve yarıiletkenin ön yüzünde imal edildi. I-V karakteristikleri 20K ve 300K sıcaklık aralığında sıcaklığın bir fonksiyonu olarak ölçüldü. Deneysel I-V karakteristiklerinin Cu/n-tipi Inp Schottky diyotları için geleneksel Termiyonik Emisyon (TE) teorisi ile uyum içerisinde olduğu gözlemlendi. Cu/n-tipi InP Schottky diyotlarının kapasite-gerilim (C-V) ölçümleri 300-10 K sıcaklık aralığında ve 10K adımlarla 1 MHz frekansta alındı. Numune sıcaklığına bağlı olarak diyotlarımızın elektriksel karakterizasyonunda değişikliklerin olduğu tespit edildi. Cu/n-InP/In Schottky kontakların sıcaklığa bağlı engel karakteristiklerinin "engel inhomojenliği modeline" uyduğu belirlendi. 20-150 K ve 150-300 K sıcaklık aralığında Schottky diyotlara iki farklı ortalama engel yüksekliğinin eşlik etmesi engel yüksekliğinin çift Gaussian modeli ile uyum içerisindedir. Ayrıca sıcaklığa bağlı I-V ve C-V karakteristiklerinden seri direnç, taşıyıcı konsantrasyonu, difüzyon potansiyeli ve Fermi enerjisi gibi parametreleri de hesaplandı.

Ti/GO/n-InP Schottky barrier diode (SBD) is obtained by growing graphene oxide (GO) film on n/InP semiconductor using easy and economical spray pyrolysis method. The effect of GO as the interfacial layer on device performance of Ti/GO/n-InP SBD is investigated in detail. The optical absorbance spectra show that bandgap energy of the GO film is 3.57 eV. The optical transmittance value of 79.5% is in consistent with the absorbance spectra of GO film. The barrier heights (BHs) that are estimated for the Ti/GO/n-InP SBD vary from 0.263 to 0.980 eV (I-V) and 1.328 to 1.006 eV (C-V) from the I-V and C-V measurements in the temperature range of 100-400 K. The contradiction between the BHs from the I-V and C-V characteristics is discussed. The mean BH values are found to be Φ b01 ¼ 0.98 eV (250-400 K) and Φ b02 ¼ 0.73 eV (100-250 K) from the Φ b0-1/2kT plot. From the modified Richardson plots based on a Gaussian distribution of BH, Φ b01 ¼ 0.93 (250-400 K) and Φ b02 ¼ 0.69 eV (100-250 K) and A* is calculated to be 12.44 and 12.73 A cm À2 K À2 , respectively. The I-V-T and C-V-T measurements demonstrate that carrier transport mechanism of Ti/GO/n-InP is well explained by thermionic emission (TE) mechanism with a double Gaussian distribution of the Schottky barrier heights (SBHs).

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